A suggestion: First verify whether that 3500lb towing capacity includes the weight of passengers and cargo. If so, then you *might* be able to tow a low-wall with a slide, but you'll be very near the 3500lb limit. If not, you can almost forget about a slide-out dinette. OUr Coleman Monterey had a slide-out dinette, and tipped the scales at 3620 IIRC loaded for a long weekend. THe slide generally adds between 500 and 800lbs to the overall weight of the trailer, and on a small tow vehicle like yours, it makes a big difference.
That being said, the slide-out is nice. It doesn't give you much more usable space, and depending on the layout, it can often compromise the available storage space, but if you're trapped inside it with a few other people, it makes a difference.
FWIW, I loved ours, but I don't miss it for a minute. The convenience of a bathroom with a shower and a DOOR, plus never needing to worry about setting up or breaking camp in the rain, then airing it back out when we get home, and having to lift the roof or contort myself into a plethora of odd positions to load the fridge... Yeah, I don't miss that stuff!
Oh, that's something else to look at... Pay close attention to the layout: Something I found important after the fact was top-down fridge access. THere's nothing more frustrating for a cheapskate like me than dragging a camper behind the truck with a fridge full of food, and having to stop and pay for a lunch.