If you don't stay near the boardwalk parking can be a bit difficult but it isn't too bad in June and if you get there early enough it won't be a problem. I have gone there during peak season (late July/early August) got down to the Boardwalk at 7:00 and could NOT get into the paid public lots. The other alternative to use (which is great) is the O.C. bus service. It stops on every block and runs like every 3 minutes. It is a dollar to ride each direction I believe. Very good transportation and very reliable and can be a bit on the interesting side around midnight!!
As far as the Fenwick Inn--it is just okay. I think it will be clean, but it is older and looks a bit rundown on the outside. Plus, it sits right out on Coastal Highway so it's really not the greatest location. I know someone who stays there and says it is tolerable.
A better suggestion (and one I've stayed in) is The Barefoot Mailman. It is on 36th street I believe. It is not oceanfront but it is oceanside and it is close the end of the boardwalk, so you could take the boardwalk train down to the rides and shops. It doesn't look like much from the outside, but is totally renovated inside, has very comfy beds (1 queen and 1 King), has ample parking that is private to the complex, and run by a family which were friendly. It was also very clean. They have website--I believe it is barefootmailman.com.
Christine