I usually park down the side street near the sailing club. Some members have said that their cars have been scraped by a vindictive resident so you will have to consider this. I have parked there dozens of times with no problems though.
There is also the hotel car park a couple of hundred yards around the sailing club. I don't know if there are any parking restrictions there but again I have had no problems.
As for the fishing, if you can hit somewhere near the middle of the river you are usually free of snags but a strong tide will pull you round and the chance of snags is there, as we experienced on Friday night. Shorter casts you take your chances.
Hope this helps.