1: They are put in the easiest place, plumbing-wise, so beside the road. Ideally, there would be a pull-off for that, but good luck there.
2: Depending on city water pressure, it takes me about 7-15 minutes to fill my 45 gallon FW tank, so double that. I highly recommend using an inline filter, so I'd guesstimate a half hour or so.
3: Yes. I'd also invest in a two-valve Y connector as well. The reason for this is if someone wants water while you are filling up, they can just use that, as opposed to yanking your hose off. I personally use a four-valve manifold out of brass, but too expensive, and it can disappear.