Some newbie questions about camo and saves

1) What can you do while camo'd without revealing yourself? Eat/drink/rest/cast/etc?

2) Who can see you, rangers and wood elves? Can they see you on where?

3) How, if at all, does any of this change with shifter forms (ie forestblend) and outlander chameleon?

4) Does the effectiveness of SVS (and other saves) depend on level? For example, while -20 may do very little at hero, is it good at lower ranks?

Thanks.