I don't own a portable GPS but the aircraft i fly most of teh time does have a 430 , whihc si jsut use as a back up to reconfirm where I am.
I don't use dead reckoning but use radio navigation exclusively. I haven't used dead reckoning since my skills test so would be rusty using that method.
Probably not a good thing if I'm honest , but radio navigation has servered me very so far so don't see any reason to move away from it. I plan my flight as IFR anyway so seems the obvious way for me operate.