Join a cycling club, it's not just about the Sunday rides. You'll find a few people you click with more and your schedules match nice enough for you to get in miles of your choosing.
If you're doing HIIT-type stuff, I'd recommend finding a serious lung-buster of a hilly loop near you and playing cat and mouse with your mates. One person at the bottom, give a head start of a certain distance (based on your respective abilities) to the rest of the group, and then hit the climb. The leaders need to get to the top of the hill without being caught by the chasers (not beaten to the top, just caught). The caught leaders join the chasers for the next hill and so on, until you can go no more. Kinda helps to break the monotony of riding the same (albeit convenient) routes over and over and helps everyone push each other forward.
If you're doing HIIT-type stuff, I'd recommend finding a serious lung-buster of a hilly loop near you and playing cat and mouse with your mates. One person at the bottom, give a head start of a certain distance (based on your respective abilities) to the rest of the group, and then hit the climb. The leaders need to get to the top of the hill without being caught by the chasers (not beaten to the top, just caught). The caught leaders join the chasers for the next hill and so on, until you can go no more. Kinda helps to break the monotony of riding the same (albeit convenient) routes over and over and helps everyone push each other forward.