Just opening the low point drains may not fully drain the water out of the lines. You may still need to either blow the lines or add RV antifreeze (the pink stuff) to fully winterize your system as you mentioned.
A wand is best for rinsing out the water heater. They are fairly cheap.
To use the antifreeze siphon hose, turn the 3 way valve in line with the hose, stick the hose down into the antifreeze bottle, and turn on the pump. Make sure your low point drains and all faucets are closed before doing that. Then open 1 faucet at a time to get antifreeze through those. I posted a thread on how I do that: My Fresh Water System Winterization Method
Hate to be blunt, but the bike rack on the bumper is not a good idea.
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263