What is the gas situation on the east coast? I've only driven around in rental cars on paved roads back there so I never really worried about fuel. Is running out of fuel a huge concern when you're travelling? What are the consequences if you do run out? I know in some of the deserts in the southwest, it can be days before you see other people, and cost in the thousands to get towed out if you're stranded, so carrying more fuel is cheap insurance.
I was in a similar situation a while ago. 40 year old FJ40 + 12 gallon tank @ 10-15 miles a gallon = horrible range. I also hated carrying jerry cans because I didn't have a place to store them outside, and they took up too much room inside. My solution was to go back to a stock 16 gallon tank and an auxiliary 22 gallon tank for a total of 38 gallons, and it's probably the best mod I ever did. Now I don't have to plan my trips around gas stations, so I have much more freedom to explore. Realistically while I could go up to 120-160 miles on a tank under ideal conditions, I was always looking for a gas station after about 100 miles, sooner if I was going off road. If I didn't know where the next gas station was along the route by the time i hit a quarter tank, i'd have to divert to a main road early hoping to find one and pray that it wasn't closed. That was always the worst feeling, sitting at the start of some dirt road and wondering if I had enough fuel to make it, or having to turn around and backtrack, or worse just continue on the highway to a gas station. Having a huge reserve supply of gas is a lot less stressful, not only because I have more range, but if something happens I know I can leave my engine idling all night for heat, or to charge the battery if I need to use the winch. It just take a lot of the worry out of things that you don't really think about until you are running on empty.
So I'd say there no harm in carrying extra gas if you have the room, and it's always more comforting to have it in case something happens. But if you've never needed it in 10 years and the worst thing that happens is you have to call a friend to bring you some, then maybe it's not a huge priority.