I can't tell you whether your car will make the trip or not. Have you been keeping up on all the general maintenance (oil changes, transmission services, air filters, tire checks, etc.)? If you have, then 70,000 miles isn't much. If you aren't confident, bring it to a mechanic. Better safe than sorry, as my Momma always used to say.
For the gas mileage, this is largely a factor of maintenance also. It will help to change all fluids to synthetics, especially the transmission and differential fluids. Change the air filter and the fuel filter. The biggest improvements will be made by adjusting your driving habits: do not accelerate quickly off of the line, keep your speed at o below 65, etc. Basically, drive like there is a raw egg on your pedals. (Personally, I sacrifice a little gas to have fun driving!)
Good luck at UCF