By the time we arrived home I had two watermelons sitting on my chest which she refused to take.
It might not have been that she wouldn't take them (well, unless she didn't try at all), but that she might not have been able to get anything. When one gets engorged like that, the pressure can kink the ducts and sucking will be useless. Frustrates the heck out some kids. Best thing to do when that happens is to express off some of the pressure before trying to nurse.
I was one of those people who never had any trouble having enough milk, until I tried to use a manual pump once. Pumping on one side at a time can be much less productive -- double-pumping is almost always more effective, and quicker, of course. I did better hand-expressing than using a single pump, if it came to that.
Many people just can't nurse easily, though quite a few give up too soon. It took 8 long days for my milk to come in, and I had all kinds of people tell me it wasn't going to work. One week after it did come in, I *had* to pump so that I didn't just about drown the poor kid when he tried to latch on; he was getting so much milk poured down his throat that he was gagging.
When I had to travel a lot, the practice I found most productive was to double-pump for 5 minutes BEFORE starting to nurse each time, then pumping for an extra 15 minutes once DS had finished his feed. By the time I went back to work at 12 weeks I had filled an entire 5.0 cubic ft. chest freezer, and had more stashed in our regular freezer, fridge, and the freezer at MIL's house. I know that I had more milk than most people, but one of the keys to conning your body into producing excess is to demand excess. When he started to drink cow's milk and I cut back on pumping, my supply declined very quickly.
BTW, it is possible to nurse in a moving vehicle, so long as you are not actually driving. If you sit next to a rear-facing carseat and lean forward, it will work, though of course you'll have to pull over for a minute to change sides. Your back won't thank you, but it is do-able. (Just for giggles, I have to tell you that I used to know a lady that actually pumped while commuting; she got one of those special harnesses to hold the pump horns hands free, and drove with a nursing cape draped over herself. She had a van, and she used to just duck into the back and tidy up when she arrived at work.)