When someone returns to working out they invariably start out hard and fast and then... they quit because they are sore, tired, and miserable.
Instead, why not start slow and easy? How about getting yourself back into the habit of working out and establishing a good baseline of strength, conditioning and movement?
This is a lot harder than going "balls to the wall" and quitting. Because by pacing yourself and giving yourself time to adapt to the new demands on your body and, this is important, you are going to be able go longer and harder soon enough without getting injured!