Crossbreed should have a supertuck that would work as a holster. As for summer dress; hawaiian shirts work well, tee shirts maybe a size larger than you normally wear., dark colors and random prints work best. If you get a IWB (in the waistband) holster then you want to get pants one size larger and a good gunbelt. If finances are an issue then you can buy an Amish belt from Hanks clothing that works well as a belt for about half the price of a true gunbelt.
If you google Amish belts it will bring up a link for Hanks.
As for the car, is there a place you can mount a holster that is easy access?
Freedom has a taste to it to those who fight, and almost die, that the protected will never know. anonymous written on the wall of the Hanoi Hilton.