Hi and welcome to TAS

You'd be looking at visiting your pigs twice a day (minumum) to feed them and to make sure they have water and depending on the quality of water in your lake you might need to take water on site for them.
Some breeds are more prone to trying to escape than others (but there's an exception to evey rule

) generally a lop eared breed (Large Black, Old Spot etc) will be less inclined to wander as they can't see where they are going as well as the prick eared breeds (Tamworths, Berkshire, Middle White) but providing you've got a good stock fence with either a run of barbed wire or electric tape along the bottom, and your pigs are well fed, have plenty of space and aren't bored they shouldn't try to escape.
For a couple of weaners, a third to half an acre should be plenty of ground to take them from weaning to slaughter size at around 6 months without rotating their pen (obviously depending on weather and ground conditions - if it's wet, you'll maybe need to move them)
HTH
Karen