hatch seal behind frig 72 sovereign 31'

[kayaker410]

After removing original frig discovered seal on hatch behind it needs to be replaced - can see a crack of daylight. Looks like other hatches on airstream might have same problem - probably original just like the frig. Any suggestions about source for seals and how to install are appreciated! (we don't take airstream on the road, and it sits outside all winter in Maine).
New frig is apt size electric. Am assuming electrical outlet from orig frig is ok to use for new one. What about gas line? Do I need a plumber to cap it since it won't be used again?
Thx