It worked! I was able to get to the heater core and get it swapped out. To answer my original question: yes. The hoses hook directly to the heater core, however you still have to access it from under the dash. Getting everything stripped down to the AC Evaporator was a piece of cake, and I didn't run into any issues until that point. I followed the previously mentioned guide and it worked really well. When I started, I didn't understand why I needed to remove the plate on the outside of the housing surrounding the AC in/out pipes. Removing the plate allows more room to move the evaporator. I also removed a hose cradle from between the wiper blades to allow for a bit more movement. One thing I wasn't ready for was all the sharp edges. Once you start getting into it, everything is factory cut edges and nothing is rounded. when moving around the evaporator I found it to be quite sharp and I have a few dings and scratches on my hands to show for it.
The guide didn't do well with explaining how the heater core is attached, other than "3 screws and 2 brackets." Let me explain. There are two lower screws that hold a bracket horizontally across the bottom of the heater core. Those were the easy part. On the top of the core, there is a bracket that seats into a metal hook on the left side, and hinges to hold in the heater core and is secured with a screw on the top right hand side. I had problems figuring that out; its hard to see up in there. When removing it, you need to remove the screw and pull the bracket out (it will swing to the left). Mine was pretty well stuck to the rubber guard around the heater core (it had leaked and made a mess). Once I had the bottom bracket removed and the top bracket in the 'open' position the core came out easily.
My replacement core was very similar to the original with a few exceptions. The top and bottom of the core were wider/bigger than the original so the rubber guard around the core wouldn't fit on the new core. I double checked with my local parts store and they said 'that is just how they are'. I guess all that the rubber does it help with rattling and dampening. I decided to just use some weather stripping to provide that snug fit on the new core.
Getting the new core in was a breeze by this point, I had my position in the truck figured out and new what I was looking at. Obviously getting those 2 brackets and 3 screws back in wasn't easy. A few colorful words and some more scratches on my hand and I had it in.
Before I finished putting it all back together, I fired it up and tested it and it leaked a little. Like other posters, I just tightened up the hose clamps under the hood and ran it a little longer; no leaks. I also noticed that my heater fan motor wouldn't run without the relay being secured to the bottom of the dash. I am assuming it needed that ground to run. That caused me to pause until I figured that out.
Here are some pictures that hopefully can help out.
This picture is from the floor of the passenger side facing forward. The glove box has been removed, the right side duct and the heater housing have also been removed. This is a good view of the AC evaporator
Here are some pictures of the new heater core with the weather stripping for padding:
