Chaney,
I know the area where you're moving!!! I now live in Ohio, but I'm from Winchester VA....not too far away! My sister still lives there, so I sometimes drive through there whenever I go for a visit
(and then sometimes I opt to go through Hancock, MD and Berkley Springs WV down 522 instead). It really depends on what size roads I'm in the mood to drive on by the time I get there!

I'm jealous!!! I'd LOVE to move back there, but dh's job is in Ohio...land of corn!
Ok...enough small talk...
to the doula stuff!: 
Homebirths are wonderful (I'm assuming, as I've not had the pleasure of attending one yet). Hospital births are more common with the general population, so if you think that you'd be happy with attending moms at the hospitals, then I say "go for it"!

Really, moms in the hospital REALLY need doulas! Long story so I won't go into detail now, but I attended a birth yesterday where I KNOW mom would've had a Cesarean if she hadn't had doulas giving comfort, listing options, and reminding her of benefits/risks
(not the birth I posted about in the "sabotaging dad post"--I've attended 2 births during the past 3 days--wheeew!). We had two doulas in this case, as I was asked to be there to observe/help a new doula. We had a nurse that was not doula-friendly, so having two doulas there was GREAT and oh so helpful!!
Your other questions: Yes, I pretty much stay there the whole time. I will leave for a
brief potty break when necessary, but only when I know that mom and birth partner are working well together. I WILL NOT leave mom alone. I've done 24 hours before, but I have in my contract that if the labor process goes beyond 24 hours and I feel that I can no longer give the quality of support that mom deserves, that I may choose to call in a backup doula to either relieve me or assist me. I've not had to call in a backup for that reason yet, but it is possible for some births to be 30+ hours. Having a plan for those cases is a good idea.
Food: I don't leave the room to eat. During the easier times of labor (often the earlier stages of active labor), I will stand back and nibble on a Luna Bar (energy bar) and drink bottled water (all the while watching closely to see if I'm needed). Sometimes I'll need to attend to mom for a ctx or two, but then I can go back to my "meal". It's just enough to sustain me, it doesn't taste badly, and yet not something so yummy that mom would wish she could have.

When I finish that, I'll take a moment to brush my teeth. (Note: I WILL NOT use my client's toilet, but I will use their sink to brush my teeth...so I'm still nearby for that.) Very often, I can time it to brush in-between ctxs. Once things start getting very intense, I don't have the time to eat (but then again...those are usually the shortest phases of her labor) and I'm too busy to think about food anyway. Of course, my description mostly fits with natural births, and with medicated births there is usually more time to potty and eat a snack....and maybe a cat-nap or two if mom is sleeping with an epidural in place. HTHs!