Even if you have a shorter time horizon, you will forgo significant savings opportunities by cashing out your TSP. For example, if you are 45, your $20,000 will grow to $53,855 in 17 years. Keep in mind that even if you really need the money, you may be better off borrowing from your TSP account.
Here, in NYS, rubber floor mats take a real beating during the winter. I use Hi-Temp tire cleaner (amazing stuff) and a brush to scrub the rubber, a procedure very similar to yours. Dressing-wise, I apply whatever looks good at the time, though, I've been really liking Tropi-Care's White Pearl as of late.
Use foam and a 2-3 bucket wash. Cannon does the same thing as a spray foamer, just better. You get a good sheet of soap that lubricates and cleans a lot of the dirt off the car making the actual wash simpler with the pad touching the car less. Plus it looks cool!