I believe my pinion seal is leaking, need advice or better yet how to change seal. I want to go on a trip and I am not sure if leak will get worse.

Replacing the pinion seals can be tricky for some that has never worked with differentials. Yours has a crush sleeve. This means that after you remove the yolk, replace the seal install the yoke and tighten it back you have to be careful not to overtighten or you will get your pinion bearings too tight and they will not last long.
Most of the time when pinion seals are leaking something caused it. Locked up u-joint, bad pinion bearings, etc... Make sure you have checked everything.