If your trailer is a 30 amp unit a pair of Honda Inverter 2000s should do. However if its a 50 amp you are going to need at least a 3000 or better.
The Hondas are hard starters since they have a fuel pump. Unlike other gensets that are gravity fed, the fuel pump needs to be primed before the Honda fires off. I usually find this takes about 6 good pulls before it fires off.
Yamaha makes a 2400watt unit that can be paralleled. The downside is that is heavier but can be handled if you have a good back.
The problem with all gravity fed units is they are difficult to adapt to add extended run fuel tanks. Hondas, with their fuel pumps are able to suck fuel from a boat tank.
Adding a boat tank will cost you over a $100 unless you fabricate all the parts yourself but they are handy.
If all you want to run in the microwave and some fans, any of the 2000 watt inverter styles will do.
That is one of the reasons why the 2000 watt gensets are popular. Use 2 2Ks when you need ac, and one when you do not. That also means if one flakes out you can run fans and such in the RV while the other is being mended. Additionally, the 2Ks are reasonably portable and one person can move them. It also means you can use both generators two different tasks when needed. I was able to drag one with me to use a pole saw to clear a path for the RVs.
One of the other gensets to look at are the Boilys. They are very popular and cheaper than Hondas and Yamahas. The 3000 watt series have remote start which means if you do wire in your 3000 you can remote start your genset allowing you to cool down the trailer before pulling in for a lunch stop.