I started this a while back (2 years maybe?). Anyhow, still not doing a lot of 'extras' like etch and all (have a Mk 11 Accurate Armour conversion I will do someday). I decided that I would put 'backs' on boxes, etc that would be hollow otherwise, plus just put on sponson covers with sheet plastic.
Before:

After:

I am also filling the backs of the suspension parts which are hollow too, which you can see a little in the above pics.
It got knocked off the desk where it was, so in fixing the couple things that got knocked off, figured I should finish it.