Training on fixed (so you get the overspeed stuff on downhills, but miss out on the high speed cornerning practice) can be made less limiting if you work out a series of routes (probably 3 or more) that force you to train different systems; if you're looking for well-rounded training), e.g.
hilly route for slow cadence seated/standing, plus overspeed downhill if no freewheel.
flat route for threshhold training/steady state stuff; use the wind where relevant to adjust required power at different cadences.
secluded short loop for shorter interval work.
Unless you live in the Fens or something, you should be able to devise a suitable rota of routes.
Training on fixed (so you get the overspeed stuff on downhills, but miss out on the high speed cornerning practice) can be made less limiting if you work out a series of routes (probably 3 or more) that force you to train different systems; if you're looking for well-rounded training), e.g.
hilly route for slow cadence seated/standing, plus overspeed downhill if no freewheel.
flat route for threshhold training/steady state stuff; use the wind where relevant to adjust required power at different cadences.
secluded short loop for shorter interval work.
Unless you live in the Fens or something, you should be able to devise a suitable rota of routes.