This summer 4 other families, that we like to spend time with, bought used tent trailers (for great deals on Craigslist as well). This includes 2 of my husband's sisters. So along with my own tent trailer re-do this summer, I also helped those 2 sis-in-laws re-do their cushions and curtains.
We did only the cushions on this first one (Tasha's). I did the plain, heavy-duty canvas on the whole thing and sewed the cute stiped material right in with it. Tasha's husband did an amazing job remodeling the entire trailer, both inside and out!! I will have to hit him up for some before/after pics!!
This other one (Cala's) was a LOT of work, but it turned out super savvy (just like her). Their trailer came with grey and burgandy interior and canvas. We stayed with that color scheme and found a classy black/grey pattern on a nice, thick fabric for the cushions.
We used the curtains it came with, but they were a bit short after being washed and dried. So we found some coordinating fabric, of the same thickness, and I added a 3 1/2 inch valance (border) to the top of each curtain with a matching tie for the middle.