[dsraven]

when doing the timing cover gasket/seal you will likely have some problems getting the cover back on unless you pull the pan. this is because the rubber end seal on the cover sorta slips into a groove and usually the cover is on the front of the engine before the pan goes on so the oil pan rail gaskets slip under the ends of the front and rear rubber ends. it can be done but takes a bit of time and patience. use permatex "the right stuff" gasket goop, liker silicone only dries faster, so you don't get any leaks. slip the cover down onto the front of the pan and use some small tapered punches, that fit the hole size of the timing cover alignment dowel holes drilled in the block, through the timing cover holes as alignment tools. install a couple of bolts in the cover and then check to see if the rubber end seal is in place correctly before proceding to finish the job.
easiest and less likely to leak if the pan is off or at least let down a bit (then you will run the chance of a leak at the rear because the sealer has let go from the new angle).
a small bit of sealer at each corner where the rubber meets the rail gasket is preferable to a large bead that goops up the whole area.
do it right the first time and just pull the pan. you could then check the bearing clearances, material in the bottom of the pan, oil pump pick up tube placement etc if you want to.