If I root to overclock, is it easy to unroot in the case of needing to return?

Source: Root | Root Your Droid

Unroot & Back To Stock
by Big Lou on Jan.21, 2010, under Guides, Root
Though Root is a powerful tool that will allow you to do so much more with your Droid, sometimes people need to completely remove it. Whether you need to turn your phone in to get serviced or would like to revert back for personal reasons, removing all hacks is a relatively easy process. If you are wanting to turn back because you are having troubles, I understand the frustration, but I urge you to stay with it and learn all you can to improve your situation. However, I can’t stop everyone, and in some cases going back to stock is necessary.
Stock is how the Droid came from the factory without Root or any hacks applied to it. Because obtaining Root goes against the Verizon Wireless TOS, if we were to have any problems with our phone that would require Verizon Servicing, we would obviously need to remove everything we’ve done. Fortunately, this guide will only target Root-specific files; no user data or Market apps will be deleted! Here is what will result from reverting back to stock:
Removal of Superuser Permissions App
Restore all default Verizon Apps
Restore stock Recovery console/remove SPRecovery and Nandroid
Remove Busybox
Disable Root-required Apps
Remove Root

 

^+1 that is the site I normally send people to. It's very straight forward and well done (very nub friendly). Just follow their guides and you'll be fine.

 

Ive been referring people to that site too whenever I see noob questions, cause its very thorough and straight forward like you said