Dave,
The dozer isn't a very good tool for road building, but it's fine for roughing it in and clearing. I have a dozer and it's the best thing I have for building roads, but if I need one built, I bring in a guy with a motor grader. What he can do in a few hours will take me several days and still not be close to as nice or smooth.
I can grade a road so it's drivable, but not smooth. My dad has been at it for months and just doesn't get it. Some people will never be able to run a dozer effectively, but most can run one easy enough to get most things done.
Without knowing you, but know a little about moving dirt, I think you're wasting your time and money to try and put in a 1,900 foot road on your own with the dozer. You will get to a point that it starts to take shape, but then it won't get any better. Then you will be pushing it around to fix one area and at the same time, ruin another.
A skilled operator will do it all at once. He will clear it in a pass or two, then grade it and be done.
The difference in power from a D7 to a D5 is enormous. The D5 will struggle to cut hard packed clay and move it. The D7 will slice through it like it's nothing. It will cut it, roll it and compact it far faster and better than the smaller dozer. The advantage to small dozers is they are easy to transport and can get unstuck real easy. Big dozers will outperform and work a small one by a huge margin. It's not like a little bit, it's a HUGE difference.
But before hiring or renting the dozer, I'd have that guy with the motor grader out and ask him if he can do the entire road. If he can drive the motor grader across there, he can do it better and faster than the D7. Most motor graders are very powerful and have no problems digging out a road on flat or rolling land.
If I had $1,500 to spend on the road and didn't own the equipment, I'd consider hiring a backhoe to take out the trees. A regular construction sized backhoe can take out any tree there is pretty quickly. You said medium sized, so that makes it easy. Around here you can get a guy to run one for
$45 to $55 an hour. Have him there for a day to clear the way for the road. Then the next day, or a week, have the motor grader come out and cut your road.
If not, then my next option would be to hire the D7 and pay for his experience. That's worth more than the dozer.
I would only rent the dozer if you were doing rough work or some light clearing. A D5 is on the small side for serious land clearing, but fine for medium trees and brush.
To take out a tree with a dozer is either very simple or very hard. HP and weight make the difference. If you have that, then the trees just lay over. If not, then you need to cut the roots and maybe dig some dirt. Each tree species is different and depending on the size of the tree, will decide on how much digging you will have to do. Sometimes with a dozer, you also have to build a ramp on the pushing side to get up higher on the tree to push it over.
It can take a very long time to take out a tree with a small dozer. The D5 is a medium dozer, so it can go either way. Operator skill will make a huge difference. A new guy will waste allot of time and get nowhere, while a pro will get it done as fast as possible.
My neighbor hired a guy with a low track D5. It's smaller and has less power than the hightracked ones. It's fine for clearing trails and light duty stuff, but they had to bring in a 325 trackhoe to take out the bigger trees. That small dozer just couldn't get anything done with the trees, or even moving the brush piles to the burn area. I used my Case 1550 to take out some trees and pile them up for him that the smaller dozer couldn't take out, but the pile was too much for him to take apart. I will say that the operator of that D5 has more experience and skill than I do, but his machine was just too small to do what they needed to do with it.
Big dozers clear land, small dozers make it pretty. Same thing with roads. The smaller dozer would be good if the road already existed and you needed to shape it or clean it up, but I seriously doubt you will be able to cut a road with it that you will be happy with. Especially if you have hard packed clay.
Good luck,
Eddie
) but I do run my business and I've seen people who have 100's of hours on tractors who can basically barely get out of their way doing dirt moving. In fact, doing snow removal this winter (26 inches of snow), my neighbor has twice the size of tractor as me with HST and I could move 2x as much snow as him. (if i was on his machine we'd have been done hours earlier)