That neutral light problem is something I've encountered also on my 225DX and my brother's 250 Beartracker(basically the same rig with an extra wheel).
Anyway just turn the key on and leave it in neutral, then start wiggling the harness under the shifter that plugs onto the switch..if it's corrosion on the contact you should be able to get the light to come on. This should lead you to the point of concern to clean and seal up with dielectric grease..
Current toys..
1986 Honda 350X..trail bomb!
1985 Honda 250SX..my main mudder
1985 Honda 250ES..Back in Black Trike
Current non-trike toys:
1990 Honda TRX300FW
1995 Seadoo GTX
1998 Polaris Indy Lite 340(Nearly new looking)
1998 Polaris Touring 500
1998 Club Car (electric)