For your first question, have you looked at Jack Daniels' training plans? https://fellrnr.com/wiki/Jack_Daniels
He has a variety of plans in his book, some easier, some tougher, some 18 weeks, some in 4 week sets that can be repeated. Workouts on quality days are a bit complex, but totally manageable with a smartwatch.
For your second question, most of the races in my area are on Saturdays, though marathons are usually on Sundays. Even then, when I've used the pfitz plans, I've had to adapt to fit a race into my schedule that fell on the wrong week or else do a tt on my own. I think Pfitz briefly describes somewhere in the book how to add races to the schedule, like how many days to taper before and after. Pfitz seems to value getting race day experiences, so I would guess adjusting the schedule to fit a race in is preferable to a tt.
Good luck with your spring full!