Sympathies! It's tough when you can't run. Pity about getting to the parkrun, as in my experience volunteering feels a lot better than sitting at home! Might be worth emailing your parkrun, seeing if they can put out a call: if someone is driving from near where you live, they may be willing to give you a lift so you can get there and volunteer.
Once you can wear a stiff-soled shoe you should be able to cycle (I could with a 2nd metatarsal fracture, anyway - 5th may be a bit different) - I put the seat down a bit so I could easily put a foot down for stopping.
Other that rest: make sure you have good nutrition, with enough protein, calcium and vitamin D. And get enough sleep. And be very glad you're not on crutches, because from experience (fractured ankle) I can tell you that's even more limiting than the aircast boot!
Lots of rest during your taper isn't a bad thing. I had an enforced zero-running taper for the three weeks before my first marathon, due to piriformis syndrome - I was allowed one gentle run of 3 miles on the Wednesday before the race, and I did fine.
Booked a room in the Belaire Suites. Not actually entered or decided on a possible qualifying marathon yet... Been a bit tied up with other things, including my cat not being well and the fact that I'm Race Director for a 5-mile cross country next Sunday.
Speaking of which, if anyone is interested, there's this great 5-mile cross country race, the Switchback 5, in Lloyd Park & Addington Hills, Croydon, 10.30 next Sunday morning... Only £6 affiliated/£8 non-affiliated (£8/10 on the day), all finishers get tea/coffee, cake and a T-shirt! (Prizes for 1st M&F, plus age group and team trophies).
seren nos: would that be this plan: http://www.trailrunevents.com/ul/schedule-50m.asp? - I based my training for my first 50-miler on that and it worked pretty well. I totally agree with a cutback/drop-down week every third or fourth week. I think a mistake many people make in training, whether as a relative beginner going for their first HM or runners going for marathon or ultra, is not giving themselves sufficient time to build up - including allowing time for drop-down weeks and the possibility of illness or a pulled muscle that needs resting or whatever.