Hi
There's no problem walking round the paddock and there's no charge for it. You can park the bike just after the exit of pit lane by the grandstand and walk down.
Where to eat! Wherever you go I'm afraid you'll be confronted by inflated prices and the dreaded 'TT Menu' (basically 1/3 the choice, 1/2 the quality & twice the price) - the TT is not a fine dining experience! Out on the course you can get decent pub grub at the Mitre in Kirkmichael and the Sulby Glen. There are numerous chippies, chinese take-aways etc in Douglas and the inevitable MacDonalds out near Quarterbridge.
As far as spectating goes it's probably worth taking a leisurely lap of the course to see what appeals. You'll find prohibited/restricted areas
where you can't go, but a few ideas are:
Union Mills from the Churchyard
Ballaugh (do this in practice week - less busy) - you can view from either side of the road.
Churchtown (aka The K Tree) - getting very popular on race days now. Very quick section with a wheelie in the middle. You can park in front of the church and watch from the field adjacent.
Bungalow (where the Joey memorial is) but pick a nice day and bring something warm - you're a long way up! As a diversion you could leave the bike one day and take the vintage electric tram from the north end of Douglas prom to the Bungalow. Give yourself some time if you do - they're not quick!
Hillberry or the bottom of Bray Hill if you want to see some really fast cornering.
Things to do: Laxey Wheel otherwise just go and explore - you're never very far from anywhere on the Island. Get an ordnance survey map too - you'll find that a great help.
Here's a route from Felixstowe to Liverpool docks, missing out as much motorway as possible:
http://maps.google.co.uk/maps?ie=UTF-8&hl=en&tab=wl
It won't take you 4 days! It may be worth trying to get to the Island earlier if you can. It's been said of the Island that it represents every characteristic of the British Isles in one small package.