Ryan I would look at the small lake as an advantage for now, the worst that can happen if you cant right the boat is you will drift to shore. You will learn to get out and in off the wire quick.
The way I learnt to be comfortable on the wire was tie one hull down to the side of your trailer on grass in the back yard put your mast up, all your gear on and go in and out, you will find all the different footholds and angles and it will click you can spend hours out there in relative privacy until your comfortable, you will also find where your harness sits and how tight you need it. Perhaps adjust your trap dogbones to a length your happy with that might be a bit higher but will give you confidence dropping your backside over the side. Boots will make you feel heaps more confident as well. While your out there get a mate to hold the boom with the sheet on it to see if you can uncleat on the wire or adjust your cleats to suit.
regards