I'm not really sure if there is a sacrificial anode for the heat exchanger - my guess is it depends on who manufactured it. A good friend of mine has a full time salt water boat, and I'm trying to remember how the bonding system ran, but if you do use sacrificial anodes, everything metal needs to be bonded together, or else the zincs are useless. Basically, it's just a copper ground wire that runs from one of the rudder bolts, strut bolts, shaft log (if it's metal), and any other metal thru hull fitting that you may have and connect to the same post on the engine bell housing as the negative battery cable. As I said before, totally overkill, but helpful if the boat is going to be in salt water for an extended period of time. That and I am just paranoid about the corrosion that salt water can do.
Lakeway is nice, but lake Travis is way down right now. There is lake Austin in that area which is constant level. I live about a hour south of there on the NE corner of San Antonio and frequent Canyon Lake. Good luck on the future career endeavors.
The boat is going to be great! 12 years of dreaming and I finally got into mine 3 years ago, and I love it! You will to!
1998 MariStar 225VRS, 350ci LT1