We've had a small, 19 foot Escape, trailer since 2014. Before this we had a restored 14 foot Shasta trailer. Shasta was a great trailer but did not have a bathroom. No bathroom is a problem when boondocking without even a pit toilet. So we "upgraded" to the Escape 19.
We towed Dora, our Escape 19, for years with a Nissan Xterra. This worked well and was a reasonable match. After adding the "Traveling Sherline Show" the weight in the XTerra was likely over spec. For Fulltiming we decided more storage and weight capacity were needed. So, we obtained a diesel RAM 2500. A big jump in capacity, and cost, from the XTerra to the RAM. If anything the XTerra was slightly lacking capacity wise. The RAM 2500 is real overkill. But for Fulltiming we decided that overkill here is a good thing. We obtained a canopy for the RAM giving us a reasonable sized "utility shed" was a real help. Fulltiming requires more stuff than a month or two.So far the RAM, and our Escape 19 are working very well. It's hard to tell the trailer is behind the RAM 2500. It allows us to travel at freeway speeds (65-70 mph) comfortably, although we usually stay between 60-65 mph. With the XTerra comfortable speeds were around 55-60 mph. The diesel RAM gets a little better fuel mileage than the gas XTerra, although diesel is more expensive. So fuel costs should be similar.
Update: In 2019 we "upgraded" from Dora to a 25' Bigfoot trailer. Dora was great but a little small for the four of us full time. The Bigfoot, named Sasquatch "Sassy" Currin, is very nice to live in. It's noticably bigger and a lot heavier than Dora. We do notice pulling it with Larry (our RAM) but it does handle well. Sassy has much better insulation, more room, an oven, bigger 'fridge, full queen sized bed you can walk around, much larger water and holding tanks, etc. She's a 2018 trailer and the previous owner put on some solar and related components. We're added our Internet components and other mods. She is bigger than Dora by 8'. This can be a problem in small campgrounds, like the Forest Service camps we like. It was a good trade off though.