If you're talking about the big gaps in the front end and lack of protection for the radiator, there's a thread in our FR3 forum that addresses this. Here's the link: http://www.forestriverforums.com/for...ser-75983.html
I did this on my FR3 and it was easy, took a little time, but it looks good and I think it's does the job. Good Luck!
Jbutch. Be very careful what you use to fill the gaps. Bug screen tend to have very small openings and will restrict air flow over the radiator and AC condenser. Most of us used 1/4" wire mesh cut to fit the entire opening from the inside of the grille. Works great to keep bugs and debris from hitting vital parts. Check out the link that Kswhodat shows and you'll get a very good idea.
I did the 1/4" galvanized screen on mine. Cost was under $20. Get a roll from local hardware store and spend an hour and you're done! I was tempted to spray paint it black before installing, but it looks good with the silver mesh behind the black motor doors.