Depends on the plane, both range and speed. We went from a King Air to a Citation to a Lear. The Citation and Lear both hit 500mph-ish which is about the same as an airliner. So actually, when you take out all the bullshit flying commercial, it's much faster.
We work in the steel industry and many steel mills are out in BFE or not near any major airports. However, there are tons of smaller airports that are close to the mills. Here's an example of a trip my boss and I did. Times are an estimate as best I remember, this trip was several years ago. Usually we hit a max of 1 or 2 customers in a day.
My boss and I left Pontiac MI at 6:00am. Landed in Indiana at 6-ish. (one hour time difference) Local salesman picked us up, went to the customer and had a 1 hour meeting. Back in the air 8:30 - 9:00 am and flew to Mobile Alabama. Not sure what time we landed but it was around lunch time. Local salesman picked us up, quick lunch and went to the customer for another 1 hour or so meeting. Back in the plane mid-late afternoon and flew to Houston. (again time difference is on our side) Same story, quick meeting, grab dinner and back to the plane. Lift off 8-ish and a 3 or 4 hour flight home. Get home at midnight or so.
Yes, an extremely long day but with only 2 of us on the plane, it's pretty easy sleeping. As a comparison, flying commercially, this would have been a 2-3 day trip.