Although this is an older thread by about four years, the topic is certainly ongoing. I will toss in a word for the classic travel trailer. I rented motorhomes, one for an extended period. I now own an Airstream trailer. You just cannot beat a trailer. I've read countless posts on the advantages of various RV types but a trailer, in my opinion, holds most closely to being affordable, easiest to maintain and most flexible. I came to this conclusion while shopping and using my measuring tape to provide comparatively calculated approach toward a decision. What I found was that trailers are often underestimated in storage capability when compared to other RV types. For example, the 72+ cubic ft of storage in a short bed crew cab pickup without a cap is ignored when comparing a trailer to a fifth-wheel's front storage area, when in reality it is prime easy-access storage! The reason it is ignored is because it is unusable with a 5th wheel! Add a cap, and you overtake most fifth-wheel offerings, at least in the smaller units. The same is true with Class A models. Yes, there is the rest of the basement but something else I found makes that difference a mute point. In several of the travel trailers, including an Airstream, there is more storage inside than a comparable Class A or the 5th wheels I looked at. I remember looking at a Winnebago Vista 26E with few cupboards. I measured each one while the salesman, catching on to what was important to me, continuously mentioned the outside storage. We looked at each compartment outside. Most were tight spaces. The nice part was the 100+ cu ft rear, but it did not really make up for the less inside stowage of even my 25'11" AS with a 72 cu ft truck bed AND nearly 30 cu ft of trunk (3 trunks on AS). Storage is not the total picture. Go price tires for a motorhome that have to be replaced every 5-6 years used much or not x6+ about $450 each- yikes!
As for slide-outs
Trailers, like motorhomes have optional slides and, for example, Coleman makes a trailer with long opposing slides that is like a condo when extended. Slides ARE nice but they too aren't for everyone. As a matter of fact, my measuring tape told a story on this point as well. Many trailers and some smaller motorhomes like the View, are narrow 74" or so. Still some are a bit wider at 96". Trailers or motorhomes that are narrow NEED slides to make up for the loss of a good 102" wide trailer or larger class A motorhome's width. Don't be fooled by seeing slides at the dinette and thinking it is bigger because of a slide-out. Consider that a 74" model is entirely 26" narrower than a wider model without slides. Slides can also be a headache. Consider if your needs really require them.
Trailers, towing and backing and diesel too
Well, most RVs now tow something but a trailer can be backed while a motorhome with a toad(car) cannot. Backing a trailer, especially a wide one, can be a challenge but it is possible. Most trailers also can be towed with a 1/2 ton truck which is really the most fuel efficient option in the RV world. A 1/2 ton later model gasser towing averages about 12mpg towing level ground. Most motorhomes range from 5-8 mpg gas and around 10-12 diesel (in smaller sizes) on level ground. Oh, and on diesel, as of 2014 a diesel has to get at least 2 mpg better to just make up the difference on fuel prices, that, the higher maintenance and the initial cost difference make diesels questionable in most cases. We are told that this year we should see around 14mpg towing figures with gas 1/2 tons due to engine mileage advancements. That is hard to beat. The final word is about the pickup. My Ford F150 is like a Lincoln that sits up high- very comfortable and quiet. When not towing I get 14 city 21 highway. A 1/2 ton truck can tow quite a rig. Just watch the payload. In may cases you do not need a large truck. I know, sounds awful but consider that my '09 Infiniti 7-spd G37 got 13 city 28 highway and was a small car AND a Crown Victoria full sized car in the same year was rated 16/24. The pickup makes for a great homeowner's tool, everyday driver and RV tow vehicle. The 1/2 ton cannot tow most 5th wheels but the question would be, do you want to lug around a second house or do you want to explore the country. Are you going to go one place to stay the winter/summer or move around more? The explorer camper usually wants something smaller and simpler.