I normally keep 40 gals gas on hand but I'm increasing that to 50 gals since that equals 1 refill for the van and 1 refill for the truck. That gives me about 12 hours of driving time, if I am frugal with the "accelerator".

Today I got another ten gals and thaqt gives me 30 gals at this moment. When I come back home next month, I'll bring that up another 10 gals to 40 gals total.