You can bicycle indoors on a stationary bike, or outdoors on a road bike. Biking does not stress any one part of the body—your weight is spread among your arms, back, and hips.
You may want to use a recumbent bike. On this type of bike, you sit low to the ground with your legs reaching forward to the pedals.
This may feel better than sitting upright. The seat on a recumbent bike is also wider than the seat on an upright bike.
For biking outdoors, you may want to try a mountain bike. These bikes have wider tires and are heavy. You can also buy a larger seat to put on your bike.
Make sure the bike you buy has a weight rating at least as high as your own weight.