The Trek, is that the one on a 3.9L Izusu engine, with a overall width of only 90"? That Safari is about bottom of Safari line, so $15,000 might be a bit high for that RV. I am pretty sure it is a front engine diesel, so be sure you can put up with the engine noise while driving.
Do you plan on towing a car to commute back and forth to work? there are many cars that can be towed 4 wheels down.
Always remember that the RV is only worth what someone else is willing to pay for it. If they really wanted to get say $12,000, they will not ask - advertize it at $12,000, they will ask for $15,000 or $18,000. You can offer something like $10,000, and once you offer that much, you can not go lower amount, (unless you find a mechanical problem during a inspection.) So find out the low and high bluebook values before making a offer, and always make the offer contingent on the RV passing a mechanical inspection.
The RV inspection should include test firing the water heater, refrigerator, other things in the RV, testing all the lights, microwave, generator, and other items.
Check the motorhome performance. See if the fuel filter has any water in it. How full is the fuel tank? A tank left 1/2 full or less for more than a year can collect water vapor in it, and absorb a lot of water, contaminating the fuel.
Has the RV been stored for a long time? That can result in bad fuel, leaking seals, ect.
Trek is one of the better RV's to full time in where it can reach 10F overnight. I don't know if anyone really wants to camp in -10F weather to much.. The insulation is not so good. You might want to consider moving to New Mexico, Arizona, or some other warm location in the winter.
Also consider most Colorado campgrounds are closed before the temps stay at 30F in the daytime, and usually will not open until April or May, when it is possible to refill all the water lines without them freezing and breaking.
If you plan on saving money, then consider dry camping a lot more. With a couple large 100 - 150 watt solar panels, and a small 120 volt inverter (100 - 300 watt range for about $45) you can keep the battery full without running the generator a lot. If it runs on LP gas, it can go through a lot quickly.
Lucky you, Colorado gets great sun, especially once above 5,000' elevation, the sun is much brighter.
SunElec.com Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
Kangen.com Alkaline waterEscapees.com