Jeff-
Do NOT buy a Hobie to get a roller furler jib- whoever responded to that obviously isn't very familiar with the comparable Hobie- the 16 (with fully battened jib!).
I had a 5.0 (#1030) for 17 years- I rigged it with a roller furler for "cruising" only- I raced with the "stock" setup. My boat had the jib halyard that ran down the front of the mast so you could adjust jib tension on the water. I simply put the swivel at the top of the forestay, the roller drum at the bottom. You have to add a small cleat on the front beam for the furler line. Raise the jib "normally" but attach the jib tack to the furler. Make sure your jib sheets are long enough to reach when furled. Slack the halyard some (you have to experiment to get the best amount), release the sheets and furl. The top of the halyard will end up wrapping around the forestay but I never had a problem with it. The 5.0 sails pretty well on just the main so if you get overpowered you can furl and then furling when launching/landing is a nice ability too. If you really want to do it "right" then you have to use a forestay with a jib block incorporated (ala a Hobie 14/18 or a Prindle 16/18 etc. with halyard that runs inside the jib luff) which is more hassle/expense/weight/problems IMO.
Enjoy the 5.0- tough boat that handles high wind well. If you have an '86 you hopefully have a lighter boat than mine which was the old solid fibreglass with stringer construction.

Kirt