Congrats and welcome to the crew! I was going to also recommend KYD but y'all beat me to it!
Already lots of good advice here. We traveled for two months last year through CO, UT, WY, ID, and MT in our 36' bumper pull and are doing 4 months in the same states this summer in our new-to-us 5th wheel. You're going to learn so much very quickly and there is an endless list of gadgets you'll "need". We're in our 5th year of RVing and I'm still buying crap on Amazon almost daily. Actually just bought the surge protector that they recommend on KYD (they have an amazon list) and it seems pretty cool so far. Can't get the remote monitor to connect but working on it...
First, you're crazy brave for doing this last minute. We started planning our summer travel and booking spots back in January. That was because we didn't start planning the previous summer until April/May of last year and wound up moving around a lot and not getting to stay in the places we wanted to for very long. You're hitting the road at the peak of the summer RV season up there. You're rig isn't small but you should be able to get into some of the smaller primitive boon docking style spots. The ones without power and water will probably be all you will find available unless you watch for cancellations like a hawk. Highly recommend you have an agenda and reservations for every night of that agenda before you leave out on your trip. I know a lot of people do the walmart parking lot thing - and I wouldn't be above it in a serious jam - but I certainly wouldn't have that as part of my plan A.
Power - as other's have said, you will probably need two of those little honda generators to even run one of your AC units. Our 36' bumper pull had a 13,500 and a 15,000 BTU unit and I couldn't run both with the 3,500 watt generator I had. Also, keep in mind that the more power you are pulling off your generator(s), the more fuel you will use. My 3,500 watt generator isn't an inverter generator but it will only run for 4-6 hours on the 2.5ish gallon tank with one AC unit running. As others have said, its the starting amp draw on the compressors that will kill your generator and that soft start system may help but I still wouldn't expect to be able to run both even with 4,400 watts of generator capacity. That's also really 1,800 W x 2 = 3,600 W of rated capacity. We have found the weather to be pretty unpredictable up here. We've experienced several days over 100 in Glenwood Springs and Ridgway State Park over the last two weeks but it finally cooled off late last week. It was the same last year. Seemed like it was a heat wave and unseasonably hot wherever we went. We work during the day so we are in the trailer and need AC most days. If you're out doing stuff during the day you could just leave the windows open and probably be fine at night without AC. However, I would not set out without a solid power plan that would allow the use of at least one unit. Keep in mind you will also need the adapters to go from the power outlet on your generator to your power cord on your trailer.
Tires, weight, weight distribution, sway bars, etc. - All VERY important and most of us learn the hard way. I think our TPMS system is probably the best thing I have bought. Went through some scary and damaging blow outs before I got that. The one we have gives me pressure and temperature which are both critical. Low pressure leads to high temperatures, side wall failures and explosive blow outs. Weight and weight distribution are critical. I bought our weight distribution hitch from the dealer and let them install it but anyone with some tools and a bit of know how could do the installation. However, you're running a bit short on time and may need to pay for the convenience of a professional installation. The idiot that installed mine didn't install the sway bar that came with the kit and told me I shouldn't need it. I needed it and would never tow a bumper pull trailer without one. I see some people using two sway bars and can understand why. Pay attention to how you're loading the trailer and make sure you're not too heavy or too light on the tongue. Also note the location of your fresh water tank and keep in mind you will add almost 700 lbs of water weight (82 gal) if you do fill it up to go dry camping. Not sure what you're pulling with but I highly recommend air bags on the back axle of your tow vehicle. Even my 1 ton DRW truck has air bags and it makes for a much better and safer towing experience. Excessive sway, improper weight loading, and lack of control due to all of the above leads to a lot of accidents, even with experienced RVers.
It looks like your trailer only has one slide. Our last one had two but they were both on the same side. It was very frustrating to level because it obviously wants to lean to that one side when you roll the slides out. We figured out the trick was to set up so that the slide side was up about an inch higher than level, then set the stabilizers and then run the slides out. We tried the plastic leveling blocks, cut up 2x12s, etc but what worked the best was a cut up rubber stall mat from harbor freight. They are about $50 and you can make enough strips to get up 4-5" - which you may need in some spots. The one I used was 4'x6' so it made 6 12" wide strip, 4' long and 3/4" thick. I used the Levelmate Pro app and device to tell me how off level I was when I pulled in and then selected the number of mats we needed to get us 1" high on the slide side. Stack them up in front of the tires and pull up on top. Wife and I got pretty good at this process and got lots of compliments for the idea. Wish I could say it was mine but it wasn't. Seriously the best and probably cheapest leveling solution we found. Sometimes the simple things are the most handy. We still carry some blocks made from a cut up 6"x6" and use them all the time. You're going to find very unlevel spots even in some private RV parks. I think the KOA in Laramie might be the worst we've experienced.
Take tools! Stuff is going to break! You're pulling a small house with all your crap in it down the road and that SOB is trying to shake itself to death. My father in law were just talking today about the tools you absolutely can't travel without. A good cordless drill is a must. Bits and screws to put stuff back together when (not if) it breaks. I just had to buy a little hand saw and a 1"x4" to make some blocks to screw a cabinet back together. Gorilla tape and glue is awesome! Cabinets, drawers, closet shelves and clothes rods seem to be popular failure points, in my experience. Don't depend on those latches for the drawers and cabinet doors. They don't work worth a crap at holding stuff in and they will break and you will find a 10lb bag of flour evenly distributed all over half of the trailer (don't store bags of flour in the upper cabinets). Also had a kitchen drawer launch itself and all of the contents across the trailer. The drawer slides disconnected and it went for a joy ride throwing silverware, knives, etc around like they were mardi gras beads. Oh, you need a hand held dyson vacuum cleaner...
You're about to spend a small fortune on water hoses, sewer hoses, power adapters, chairs, grills, outdoor stoves, cook ware, silverware, plastic plates and cups, coffee making contraptions, organizing bins, head lamps, electric heaters, a bigger trailer, a bigger truck for the bigger trailer, more crap for the bigger trailer.....or maybe that's just me. We started with 0 experience, just learned as we went, still learning and having a blast. Have fun!