Don't remove the front cover unless you intend to remove the heads! The front cover is sealed on top by the head gasket, and although the manual tells you it is possible to R&R it without taking the heads off, chances are it isn't going to seal worth diddly if you do, so you end up doing head gaskets too.
Unless you think you need valve work, leave the front cover on. Lower chain rails don't get the slap from a loose chain on startup, so they almost never cause trouble anyway, wait to do them until you need to take the heads off for some other reason.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!