Sound like you are a bit frustrated. Probably the first thing to do is to determine the feeding pattern and preferred trails and areas that the deer are using (which you said you did). Note the time that they are visible, starting to feed. Part of this hunting is hunting for a good shooting location that provides good visibility, some degree of protection from being seen, and good safe firing lanes.
Look for a comfortable spot to hide and wait - there might not be such a thing so you may want to check out the little ground blinds that archers use. We just killed four deer by setting up in the middle of a large stubble field, wrapping a sheet of camo net in front of four guys to break up our shape. Was more like a goose hunting scenario than a deer hunt but it worked.
As for your shooting position. Strongly suggest that you check out the shooting sticks and bipods from Stoney Point, the new Polecat bipods are very sturdy and easy to use. Sounds like you cannot setup for prone shooting, that is the preferred shooting position for our type of hunting (some ultra long range guys actually use portable shooting tables, depends on the weight of your rifle, access, terrain, range etc). I have found that supporting the fore-end and butt makes for excellent shooting regardless of position, suggest you give it a try.
If you have to shoot from sitting because of terrain and cover the sticks/bipods are amazingly stable if you use two sets - front and back on the rifle. We like to use large camo panels of lightweight mesh sold by Hunter's Specialties to make a simple ground blind or simply wrap it around you loosely.
If possible I sit on a little folding stool till the deer show up, then try to shoot from prone with a Harris or crossed sticks, always have a small beanbag along for the rear of the stock.
Once in a position we laser key objects so we know distances, sometimes draw simple field sketches with distances on them. We mostly use good binocs since we are shooting inside 700 yards. Find that the spotting scopes are not necessary but set them up if the shots are going to be longer. I can usually see bullet trace with my 8X binocs so can call shots fairly well with them.
I like to put out a wind indicator at my shooting location, so I can monitor wind direction - might be as simple as tieing some yarn on a stick. I use a Kestral 3000 or a Brunton Sherpa wind meter
for velocity and air temps.
Patience is essential. Try to figure the feeding pattern so that you get out an hour or so early if you do not like to sit for long periods of time. Make sure your drop chart is handy so you can apply the proper elevation, dope the wind and let the fun begin.
Where I live this only works for part of Oct. then the weather is too cold and we don't hunt from ground blinds anymore
Good luck with your hunting,