Depending upon what kind of trailer you get will determine how much truck you should buy. I've owned only 2 kids of trucks in my lifetime... a Chevy S-10 Pick-up (years ago) and 3500 duly's. Maybe it's just me, but would not want to tow a trailer with anything else but a 3500 duly, or F350 duly. The right set-up and towing is a non-event. That is the experience you want. The incorrect set-up and towing is a total white-knuckle nightmare and you'll hate it. Go bigger, you'll NEVER be disappointed when it comes to towing.
About 4x4 and towing. I have used 4x4 towing only a very few times in over 20 years to towing trailers, and that was ONLY in snow. But, I use my truck as a daily driver. We live in the country, work in Fishers, and need something that will go through snow with no issues. So when we have snowfall, the car gets parked, and that 4x4 works very very nice over these back Madison and Hamilton County roads! I use 4x4 in the winter a lot. But not for towing. 4x4 adds no benefit towing, unless you are on a slippery surface.
EDIT: Just saw a previous post with your trailer stats.... 3/4 ton will work OK for your trailer. But ..... well .... I'd still rather tow with a 1 ton.