My husband and I started our thru-hike on March 4th, and entered Mass. on July 3rd. This was right after taking a few days off to visit NYC and a relative. I would say our pace was average. As you get into your hike, you will be able to guage how far along you will be by June and start to plan accordingly. The ATC has a list of shuttlers state by state, and hostel owners often shuttle or know of shuttlers. There are so many towns and road crossings thru the mid-Atlantic states that you can probably arrange something from just about anywhere. While I wouldn’t recomend carrying a phone usually, maybe one of your family members could mail you one to carry right before the meetup to help with arrangements.
I know you aren’t asking - but I will also caution against meeting up with friends. Many people on web sites like this one warned my husband and I against it before we started our thru but we did it anyway. It was TOUGH to say the least.
The best kind of meetups I think are very short (like 1 day) where the friend/family does all the work to find you and plan. But that isn’t how it usually works, and the logistics can be a huge drag. Be flexible, try not to lock yourself into anything to soon. The best part of the trail for me was freedom from plans / deadlines / etc.
Jitterbug