JoeySr

How many ounces of CS are you using? Whatever it is, try adding 1-2 more. Just realize the FG won't give a thick foam like the FC. It's simply not made to do that, I think regardless of the soap used.

And my wife thinks I'm nuts for trying to clean the cars while we are "on vacation" haha.  
 
I would echo what some others on here have said, seal the glass, it's a definite must!  I'd bring along detail spray and a few drying towels, glass cleaner / brilliant glaze, and either total interior cleaner or leather conditioner, just in case someone spills something in the interior along the way.  Coin-Op car washes unfortunately can be your best friend for long trips like this one, just to keep things from getting too gross.
 
I'm from Pennsylvania originally, not sure which route you are traveling, but if you happen to get near / around Pittsburgh check out one of the original Primanti Brothers locations (downtown), they have their chains in other states now, but from my experience, nothing beats one of the true original downtown locations.  If you have the time, swing by Gettysburg, PA (less than 90 minutes from Baltimore) if you want to check out any of the civil war / battlefield stuff, July is when the re-enactments of the battles take place, so if you go before that it won't be as crowded, definitely worth taking the time to check out.
 
 

Check you two out!
 
I love the duck fat fries at DuClaws and the pit beef and hand cut fries at Chaps.  Chaps has been around for over 30 yrs and is a Baltimore staple, and has been on DDD and other food shows time and time again.  Pit beef  to my knowledge is a Maryland thing and more so a Baltimore thing...I highly recommend it!

Oh ok very cool!
 
If you have not been to Andrews before, I just want to throw out there that Prince George’s County MD is one of the most violent and crime ridden areas of MD....first being Baltimore.  So just keep your eyes peeled and head on a swivel and keep the family safe.  I also see that you are former Fire Dept,  PG County also has some infamous fire departments that would welcome a visitor with open arms.  I live about 1.5hrs from Andrews, but if you need anything or more information, don’t hesitate!
 
Take Care

Seal the glass def a must you will thank yourself for that one. How long will you be gone? That can have a big effect on towel quantities, coin op places will be a big help and if your sealed up well will blast off most of what you need with just water. 
 
I would bring Glass cleaner, leather and interior cleaner, and waterless (or rinseless in base form with a bottle for making waterless on the fly) 
Towels:
Glass towel, Id figure 1/4 towel per day and would really only concentrate on the front glass. 
Utility Towels, id bring 2 
Borderless Grey or Single softs, as many as you can fit reasonably. (These can double for waterless as needed) 
Dont forget a spare bag for the dirty towels and possibly one for partially dirty. 

Where around the DC area are you heading (PM if you want).  
 
I keep some towels in a ziplock bag at all times, and squeeze them under a seat just fyi.  Definitely like Chris said seal everything up inculding windows/windshield.  Personally I’d doube and triple up the front end because of bugs.
 
Not sure how strapped for room you are, but you could always get small travel bottles at wally world and take a bunch of different chemicals with ya.  
 
Either way have fun and be safe

Don’t forget coin ops can be your friend to spray off any big stuff or bugs. Should make it easier to do the WW, too.

x2 on sealing the windshield.  The video with Adam where he cleans and seals the windows on the rental SUV always resonates with me because I hate dirty windows.  A "must have" for me would be Glass Cleaner and Glass Boost.

Before you go, a good base of sealant or wax will allow the road crud to come off easier during the trip. Then, I’d recommend you pack a bottle of Waterless Wash and some blue WW towels, and maybe some DS and Single or Double Soft towels. Assuming it’s not more than light dust/dirt, rain spots, fingerprints, etc., Waterless Wash is ideal (anything more and you’ll need to just wait till you get back...you can also dilute Rinsess Wash 16:1 for a Waterless Wash-like solution at a fraction of the cost). For the inevitable bugs, spray then let soak for a while, and lightly rub off what you can. DS can also help with some added shine and protection. Glass Cleaner may be worth adding to the mix, but you can get decent results with the WW in a pinch. Brilliant Glaze will add some serious, albeit short term shine with very limited protection and is easy to apply quickly by hand. You might also consider packing some MRB to clean the towels along the way should you have access to a washing machine. Those towels are going to get nasty. Get and Adam’s bag to keep it all together.
Have a safe trip!