I was away from riding for some years also and now just getting back into it. What I did was some indoor cycling first. Look on craigslist for the cheapest bikestand trainer. People buy these, never use them then sell them for $60 on CL. You can get good deals.
With a smooth/slick rear tire on a roller, there are no bumps. Ride indoors and do two things: (1) get back in shape, (2) adjust your bike for best fit. Moving the seat and bars and the position of your cleats makes a difference in comfort.
But mostly you need to get back into shape. Start with 15 minute rides. If you are even a little sore the next day skip riding one day. But you should be able to do a short ride every day. Then up the time to 30 minutes. When you can comfortably ride indoors for 30 minutes THEN take the bike back on the bike path.
You need to ease back into this and over doing t is not good. The best indicator is that you should recover from a workout in a day if not you are going to hard. Your body makes changes durring the recovery period, NOT while riding so you have to allow this recovery, hence the need to start slow.
Indoor rideing can be lower stress. Set a class or water and a towel on a table near by and tune on the TV or read a book.
Buying a new bike will not help as much as buying a $60 used training stand.