Oil cooler line replacement

Ok 96 Jimmy with a oil cooler leak. looks like it's off the cooler side of the lines. I figure if I'm going to put the time in to check the orings I might as well replace the lines as well (84000 miles). So here are my questions.

1. How much time does this typically take? 1-2 hours?
2. I have read about have to break the engine mount loose. Is this true?
3. Any special things I should watch for that aren't in a manual (like the stupid fuel tank evap fitting that isn't listed anywhere)?

thanks up front for any help.