>> I'm considering is hiring a guide for a day or two,
at 30-50USD/hr, not including vehicle.
Taxi tours: 3 hours 15000yen - 8 hours 35500 yen, taxi drivers with limited English
Goodwill Guide: free, you pay for all transportation but meet+greet isn't really what they would do. I certainly wouldn't do it as a volunteer.
>> I'm especially fearful to getting from the airport to Tokyo
Pick a hotel that has Limousine Bus (just a bus) service - and watch out for the schedule.
http://www.limousinebus.co.jp/en/ Or fly into Haneda and hire a flat rate taxi @ ~8000.