I would not try to go from 3-4 miles to 30 miles. When I first began to ride, I attempted a 30 mile ride with a club, and I got 6 miles and had to turn around (for a total of 12 miles). They said it was almost flat along the coast, but it had alot of hills. I felt badly that someone had to turn around with me and not complete the ride. After that, I joined a beginner bike class, and we went from 8 miles to 25 miles in 8 weeks. It really takes alot of riding to increase your mileage. Four months later, the club was doing the same ride again. I went this time, and it was so unbelievably easy!!! Here I thought it was this big thing to overcome. Now I ride about 15-25 miles 3-4 times a week. I did a 32 mile ride with some faster people a few weeks ago. It takes that kind of time riding to increase your fitness. It also depends on whether the ride is flat or hilly. You can go much farther on flat terrain. So, I would recommend trying to increase your mileage 2 miles farther each time. It is possible, but you have to work up to it.