I check the map, memorise the order of the towns on the journey and print out a large scale map of the last mile. If I get lost I just wing it, read the road signs and hope for the best. If all else fails I stop at the next convenient place and check the map. I do sometimes 'fly' key parts of an unknown route on Google maps, satellite mode before a journey
My knowledge of the geography of the UK is sufficient to get me to most places just using road signs. It is the last mile I need the detail for and from experience as a passenger, this is where satnavs are of least use.
I confess, I love maps, especially OS maps, road maps are rather dull but sufficient for their purpose. Many years ago I navigated DH from Penrith to Alnwick, across the fells in the dark on minor roads. We were still engaged at the end of the journey. He trusted my map reading then and still does.
Recommendations please, for a stopover on the way to Loch Tay