how many hours does it take to remove and install the engine on a 3.0L pick up truck?

With or without air tools? With or without experience? Do you have a real engine hoist?

Someone with only hand tools, no experience, and an engine hoist can probably remove it in about 4-6 hours.

4-6 hours to remove, another 4-6 to reinstall.

If you take 4 hours to remove, you are going to take forever to reinstall. Reinstalling always takes more time than removal as you need to recheck the installation process.

I would recommend buying a repair manual and reading through the sections on removing and replacing the engine before trying it.
https://www.2carpros.com/articles/mitchell1eautorepair-car-repair-manuals