Is there difference in seeing in town where there are houses and roads and especially in winter with chimneys and heated houses vs countryside where is grass and forest? I have telescope on balcony looking above block of flats. Would my autoguiding improve if I change the scene to more remote site?
This is a bit more complicated than you probably realize.
Telescope on a balcony. What happens if the building sways a bit in the wind? That has nothing to do with seeing.
You're going to have 3 or 4 different kinds of seeing, no matter where you go.
1. Inside the scope. If the scope hasn't acclimated to the outside temp, you will have bad seeing inside the scope itself with tube currents.
2. Local seeing around the scope... like dome seeing, or your body heat drifting across the light path of the scope.
3. Local seeing in the area, such as heat plumes from chimneys, or heat rising off rooftops or pavement.
4. Atmospheric... like wind becoming turbulent when it goes over the mountains, or from the jet stream being overhead.
So you really have to consider each of these.
And just to complicate things, I've seen great seeing in the middle of a big city, and terrible seeing in the Pine Barrens where I observe in New Jersey because Pine trees are notorious for outgassing and messing up the seeing.
In general, the seeing is going to be better in the summer, and then the heat island of the city won't matter much except you don't want to be looking over any hot roofs that will re-radiate heat all night long. In the winter, the seeing is usually going to be worse, and going to the forest might not help. And if the jet stream is overhead, no matter where you are, you can forget about it.
In any event, disregarding seeing, if you can get to the woods to shoot, it's going to be darker, and you will get better pictures in a shorter amount of time then from your balcony, so if you can go to the woods, why wouldn't you?