Hi bish, welcome to the forum. Please don't worry Kent isn't that scary (honest) and there's lots of us that can help you.
Non-selective boys schools /co-ed schools in the Tonbridge /TW area are:
Hayesbrook
Skinners' Kent Academy
Bennett Memorial - church school
St Gregory's - church school
Mascalls - Paddock Wood
Hugh Christie
Then there's Knole Academy and Trinity (church school) if you decide to come nearer Sevenoaks.
I'm sure I must have forgotten a couple so this link may be useful if you haven't settled on a house yet:
http://webapps.kent.gov.uk/KCC.SchoolSe ... fault.aspxAs for getting to school, West Kent children are very used to using the buses and trains, huge numbers do it so your DS won't be alone and KCC operate a very reasonably priced bus pass scheme.
Good luck with your search and if you need anything else I'm sure somebody will be able to help.