Hello Mike,
It’s tricky to give precise advice without knowing a bit more about your observing ‘site’. Any kind of fixed pillar in a lawn, or backyard, can be a huge advantage, even if a crude observatory is not possible. Setting up each night is a huge hassle, even for someone without a bad back! Before the planets sank so low I used to do quite a bit of planetary imaging with a 12-inch Newt. on wheels.
See: http://martinmobberley.co.uk/images/Orion12inch_f5p3_mpm.JPG
The entire telescope just rolls out on a carpet from a wooden shelter attached to the house wall. After the telescope was polar aligned for the first time I knew by looking at the angle the base/wheels made with the lawn/paving slabs when the base was correctly aligned. In fact, under the carpet I made crude marks on the slabs indicating where the wheels should sit. This only guarantees polar alignment within a few degrees, but for 2 minute imaging runs on, say, Jupiter, it is more than good enough. Yes, you will get declination drift and a small amount of field rotation, BUT, compared to the problems of atmospheric seeing it will be negligible when the images are stacked with, say, AutoStackert! Deep Sky imaging is more of a problem (especially if you want to use accurate Go To) but, as Grant says, even with Alt-Az systems you can do very short exposures before field rotation trails the stars.
On a few occasions I used a small, fast, system on wheels to image big Deep Sky objects or comets like 17P/Holmes. This was a160mm f/3.6 Takahashi E160 on a Vixen Sphinx mount. See attached image…..
Occasionally this wheeled out on plastic rails, but on other occasions I just wheeled it around the lawn and literally ‘guessed’ the polar alignment by aiming the tube along the polar axis and getting Polaris centred. This was more than good enough for multiple 30 second exposures! If I was planning several sessions over a week I’d just leave the system outdoors covered with a tarpaulin!
Martin