Sweet!! I had this as my first boat too!!
She's a fine boat to learn on. The gel coat crazing is no big deal. I wouldn't put a lot into her quite yet. As you said, dip her on the water (probably has a trailer, right?) and see how she works.
Regarding the tiller and rudder, you thankfully don't have anything complicated there. It's not a "balanced" rudder and has no "wing" aspects to its shape. It was simply a piece of metal rigged to a tiller arm. You can use aluminum or well painted steel
. It was approx 1/4" thick.
Holes were drilled into it and it was painted with bottom paint
(use the proper aluminum paint). I wish I had the shape to give you. I can only describe that it was rounded at the bottom, rather than a square rudder. But... it was completely flat (no "wing" aspect to it)
Definitely upgrade your pintles and gudgeons though. Mine cracked and broke pretty quickly with some good hours on them. Go up several sizes from what you have in the photo
. Those are the stock ones and they are very weak.
As Dan said, West System is good. Go to West Marine
and take a read of the packages and any info you can to figure out how to use the West System products - or look online.
Another weak spot on these is the little "divider" with compression
post that holds up the cabin
top, which in turn holds up the mast. Mine always "dishpanned" in until I put some extra structure in there to keep it up.