H.,
We have a "toy hauler" travel trailer and a Polaris Ranger (kind of like a 4 wheel drive golf cart looking thing) and a quad. We love to go out camping and it is great when we can do it. We have 2 boys - a 4 y.o. and a 1.5 y.o.
We bought ours used for about $17,000. New they go for $30,000 and up (for what we got). So not inexpensive by any standards. Some years we've used it a dozen times and the past 2 years (pregnant, shattered my knee cap and then had NO vacation time left, LOL) we've used it once.
I love it, love it, love it and I love camping in it. We have the best family time with it.
That said, we also pay $125 a month to store it (we don't have RV parking at our house). And we just spent $1000 fixing the generator and other misc things because it had been sitting for so long and that was right after we pitch out close to $1000 for new tires, etc... Plus it has to be registered each year, insured, etc...
So, in the grand scheme of things, I love it but it is a total money pit. For no more often than we really get to use it, I think it would be much more cost effective to just rent one (the rent isn't cheap but you then don't have to maintain it or store it or make payments on it when you aren't using it - so unless you are going to go a huge amount, renting is probably more cost effective). If you do buy one, buy used and not from a dealer. It is a lot like a car in that if you do buy a new one, the second you drive it off the lot, it loses half or more of its value.
My dad bought a regular travel trailer, a really nice one. He's used it a couple of times (I think it is a 2005 and I think he's used it a total of 3 times) and it is in perfect shape. I think he paid right around $30,000. Now he's trying to sell it and he's got it listed for $13,000 and has had NO calls. All I can say is buy used (just make sure it is in good shape - like my dad's is barely used and you can find those deals if you look) or you'll lose your butt on it.
All that said, if you are going to buy one, get one with a generator already in it. To add them after market is really expensive (like around $5000). If you are going to be anywhere that you can't plug into power, a generator is REALLY nice. We have a microwave, a tv/dvd player, an air conditioner, etc.. in ours (and you have to run the generator or be able to plug in to run them).
I think ours is about a 26 footer and that is a nice size. It holds our toys and is still small enough that it isn't a nightmare to pull or try to park. If you are going to do any campground parking (especially up in the mountains) if you get a really long one, you'll have a hell of a time finding a space you can get into.
And obviously you have to have some sort of a vehicle that can pull it.
Happy camping!
:-)T.