Im disappointed the experts havent commented. I'll have a go, use the left mouse button in Blender to move around, and the numpad, I think its 5 to change the view (perspective) and you use the mouse again (left mouse button to move around)
Id find some interior shots of the bus and dont focus on the seats but the moulding of the interior. So wheel arches, back bench space, and work towards the front, or start front to back, these buses are a lot easier to model thankfully as its pretty square unlike moden buses all over the place.
If you get stuck PM me and I'll try to help where I can. But id expect the experts to help too.....