i had a similar time. i had 4 months off after christmas.i like to run track but was too late to get as fit as i wanted so just started running really easy.
i wanted to get a base in and not worry about anything else but running. no intevals, nothing. like you said, i really enjoyed running again. i did nothing heroic but just ran how i felt every run.
i got fit really quickly and just did it through running how i felt. sometimes i'd go slow with a group or just go and run 30 mins hard if i felt like it. although that is classed as a tempo run normally it didn't seem that way as i didn't plan anything.
i want to increase my mileage too as i have been running in the 50's for 3 months now. but i have always struggled to do it. someone suggested a ladder effect though recently that i may try. you may have heard it but here goes;
say you're at 35 now. do 40 next week, then return to 35 the week after. then go to 40, next week 45, then back to 40. next go to 45, then 50, then back to 45. see how it works.
you will go from 35 to 55 in 11 weeks. it's quite a long time but a real safe method and because you keep backing off before the next level you can run at a faster pace. i know a lot of people here say the pace doesn't matter but it's important for me so this way i get to keep the pace while increasing the mileage slowly.
hope this may help