I'm right in this same spot now.
I've got the old tank out, and other than needing some good cleaning a new vent tube bung and maybe a coating of epoxy paing, it's in decent condition.
The hoses on the other hand have to be replaced as they are dry rotted and letting gas in my hull.
I CAN'T SEEM TO GET THESE THINGS OUT!!!
I found the really hard glue stuff in the fuel coffin where the tubes come in and was able to remove that, but while reaching in the front portal by the filler it feels like the hose may be foamed in!? (Really wish I had some sort of endoscopic camera here!)
How did you get yours free? Mines a 85 so it might be slightly different, but any suggestions you have are worth a shot!