We use Bishopthorpe launch too. Call the number when you get there and he comes down to collect the fee.
Acaster Malbis is okay but very steep.
We do our day ticket online and do get asked for insurance info before they issue the pass.
Speed limit is strict. plenty of house boat owners and anglers ready to point it out if you go over!
We usually go up to museum gardens and moor up there. The area above york is quieter and boats do seem to test the planing up there more