Don't know how I missed this earlier but i'll toss in my
anyway (better late than never right?).
For Shermans and other vehicles with similar suspension i paint the suspension parts and the road wheels the base color on the sprue. After assembling the bogies i attach them to the hull (which was assembled while the bogies dried) and the whole thing is given a coat of paint. After that i paint the rubber part of the wheels.
For all tanks the turret and hull are base coated seperately to ensure that there is paint under the turret and the camo (if any) is applied with the turret in place as would be done on the real deal.
If you attach the tools, tow cables, etc. before painting use very small amounts of glue at the attachment point and you can slide paper between the handle, cable, etc as a mask.