There's North Denes heliport (EGSD) just west of Caister, north of Great Yarmouth. It's a little drive from Lowestoft, and looks like it's mainly rig traffic. I've no idea if others can use it.
Check out
http://www.pprune.org/forums/showthread.php?t=140093 - bit old, so no idea if the info's still true.
Not aware of any suitable hotels, but I'm always there for the airshow, and the Blue Eagles must park somewhere... Very good show by the way - seaside and Blue Eagles - what more could you want?
Let us know what you do in the end - I've often toyed with the idea of flying down to the airshow one year - maybe when the kids are a bit older.