As OP notes, it's usually not a problem on rides of 2 hours or less. Plain water will suffice.
On longer rides, almost every gas station has orange juice or V-8. Both are great sources of salt. You may want to water down the orange juice, or wash either down with water.
If that doesn't work, try a Nuun tablet in 20 or 24 oz. of water. Ice water, if possible.
French fries or Fritos are great ways to consume salt at a stop. Drink a lot.
How to replenish water, salt, and calories on long rides is definitely YMMV territory. Try different things until you find something that works for your stomach. And be ready to try something different if plan A goes to pot.