That's not a bad idea if you want to be sure you can get it done right away. If yours has the AIR tubes, then you need to make sure you are getting a head that has the holes for them. Not all 300s had the AIR tubes. I would also recommend getting new head bolts. I used my old ones when I did my head gasket and didn't have any problems but technically you aren't supposed to reuse them.

The good news here is that the 300 is one of the easiest engines out there to work on. If you have never done a head gasket before, there's no better engine to learn on than a 300. I easily got mine done in an afternoon. I'm pretty much like you, far from a professional mechanic but mechanically inclined and willing to learn. I've also done all my own repairs and maintenance since I first started driving. (I'm 31 now) Only thing I ever took a car to a mechanic for was a clutch in an old Honda I had when I was about 20 or 21, that was only because I lived in an apartment at the time and the landlord wouldn't allow vehicle repairs in the parking lot.

 

If you are going to replace the whole head, consider going ahead and getting a new air tube and fittings. You can get one from pciinc.com for about $100 for the tube and the fittings. If they are out of stock, let me know. I have an extra tube and I believe a full set of fittings that I ordered from them last year when I did mine. I ordered two since they can be hard to find.

If you are planning on using the old one, be sure to use a line wrench to get the fittings out of the head (9/16 I believe). They will deform easily. Use lots of liquid wrench/wd 40 before removing them. Same thing on the egr fittings and exhaust bolts. Start spraying them as soon as you park the truck for the work.

Be sure and have something to put headbolts and pushrods in to keep them in the correct position. I even did the same on the intake/ exhaust bolts.

All in all, it wasn't difficult. I just took my time and took lots of photos, especially for the vacuum line routing. Tape labels work well, too.