After looking for a while I finally bought a small (relatively speaking) TT. I wanted a small TT with a built in generator and large tanks. I wound up with a used small 2008 Cherokee 17DFWP TH. It has 62 gal of fresh water, Has floor space for three large Collies, Is generator ready with a built in fuel tank. While the trailer is 17' overall length is 22'. High ground clearance. 15" tires with over 2k# payload. Now the bad. It's heavy at 4880#, and they call it a lite. Has almost no storage. A little tall and is stick and tin construction. They stopped making this model so I had to buy used. It's clean and well cared for so I did not mind. I liked the small Wildwood 18srvt but no place for a generator. It was less tall and only weighed 3200#.
62 gallons? Those must be thirsty collies! If you tow it dry, it'll weigh 500 pounds less, if my math is right (which it rarely is).
Congratulations! Where are you going on your first trip??
The first camp out will be at the dealer. I have to drive 9 hours to pick it up. They will have it set up for me to use. I bought this for a trip to Alaska. I'm towing with a 3/4 ton Diesel so the weight will be more of that cheep fuel.
With the CO detector, propane detector and refrigerator using 35 amp hours per day, it is really difficult to go a week with 220 amp hours of battery power, unless you have at least 100 watts of solar panels. And 100W will barely put back the 35 AH used daily by just the refrigerator and detectors.
SunElec.com has some good deals on solar panels, in the $2 per rated watt range. If you select a 12 volt panel, then a low cost controller can turn it on and off for about $65. They where selling a 195 watt panel with 18 volt output (12 volt nominal) for $265 a couple of months ago, but don't have any more in stock last time I checked their website, you can always call and ask about current stock, and when more 12 volt panels will arrive.
My suggestion is if this will be a hunting trailer, or going out on snow machines, then use a 6,000 Btu Olympic Catalytic heater, no battery power at all, and you need to leave two roof vents open slightly, I used Maxx air covers on all my roof hatches, and leave a window slightly open. The RV should stay toasty warm even at 15F outside. Mine keeps my 30' Bounder at 70 when it is above 25F outside, and I run the furnace a little bit if below 25. I have dual pane windows, basement that is kept warm, and a little more length, so I think you should stay equally warm with a shorter RV, less insulation, and single pane windows.