The gasbuddy or similar calculators should help. The good news is gas prices are down compared to years past, so that should help a lot. If you're deciding vs. flying, also factor in tolls (not too much from PA), lodging for a night or two each way, the impact of depreciation on your vehicle (2000+ miles is a measurable percentage of your vehicle's life/value), etc. To me, the biggest factor is time. Driving takes a minimum of a day (or more) off each end of a trip. Not so bad if you're going for a couple weeks, much more so if a week. Another way of looking at it is: to get the same amount of time (vs. flying) at Disney, you would need to add at least 2 days to your trip (and thus valuable vacation time)...or, for the same trip duration, have less days at Disney.