You could certainly find a 1/2 ton to meet your needs, but if you plan to do long distance towing, the F250 will be more stable, which means a more enjoyable towing experience. If upgrading to a 3/4 ton is not an issue to you, it is worth it. Now if you needed it for a daily driver, maybe not the best idea. Your call, but while towing, there is no such think as overkill in my opinion. The only advantage of a 1/2 ton would be the 3.5 EB might be a nicer towing motor than the 6.2 V8 in the 3/4 ton Ford. I'd rather give up power than stability however and the 6.2L will not have any issue at all with a trailer the size of yours.
Also, if you want to pack a lot of stuff, more payload is better.