I have similar 2200 and 3000 units and they are extremely large, bulky and heavy. You'd be far better off with a small generator.
Given the size, weight and benefit, I just don't see this as a great idea. In RVing, particularly with smaller units, weight can be an issue and some of these weigh more than 125lbs. My back can tell you first hand.
UPS units do generate heat and significant sound when the inverter is actively creating AC power from the DC batteries and they don't do it for a long time either. I had 2 or 3- 6 amp max rated servers on a 3000 and got about 1 hour 15 minutes and as the unit aged, those quoted times lessened. Replacement batteries are not cheap either and you have to replace them typically every 3 to 4 years, or more, depending on how many cycles the batteries are put through. Running these in conjunction with wet cell deep cycle RV batteries I am also not sure is such a hot idea if that was the route you were thinking. These units are designed in a specific way and the manufacs tell you not to modify or change out to unapproved batteries. Normally I like most like to push the envelope, however with lead acid batteries, you have the equiv of 2 to 3 sticks of dynamite. Not something I'd consider experimenting.
OTOH, if you had a generator, normal coach battery or batteries, an inverter/charger, you time for power production would go up 3 fold, weigh less and have far less TCO (total cost of ownership). You could replace the batteries on these larger UPS units 3 times and have spent as much as you would have on a 900 to 1000 watt generator. Getting and LP powered generator provides on less fuel source to haul since you already have LP on board in most cases.
Oh and not only do I use a gen with the RV, at work, we've started to abandon the rack mounted UPS systems in our large data center due to cost of the replacement batteries and benefits the smaller 2000 to 3000 units provide compared to a large Liebert or GE monster in line UPS, we have also placed a natural gas generator in service as well. There are still great applications for these rack mount UPS units, but in your application and in our data center, they make less and less sense.