If I am not mistaken winter squash, pumpkin etc. can be canned in a pressure canner as cubes. They to not recommend canning mush because the jars have a hard time reaching proper temp.
I remember doing butter nut one year. I would drain and mash.
Just remember squash is an alkaline food so give it a full 90 mintes at 10 pounds for sea level. Consult a chart if you are higher than that. Be sure to examine the jars for bulged lids or discoloration before using.
I've canned zucchini and yellow summer squash. I'll never do it again. It is pure mush. I prefer to blanche and freeze it. That is real mushy too but not as bad as canning it. I really don't have a good preservation method.
One thing I have done that worked OK. I shredded zucchini, measured it out for the right amount for my recipe for zucchinbi bread, 3 cups I think, and froze that without blanching. You get a lot of liquid with it when you thaw it, but it makes pretty good zucchini bread. I add the liquid in with the zucchini to keep the zucchini bread from being too dry.