I know I am not much help here. I have just started (again) to lose weight.
At the moment I am hoping to initiate a routine to start riding my bike whenever I am not asked to do a 12 hr work shift.
Weekends seem to be my best chance to start a regular cycling routine.
At this very moment, my knees and legs are too weak to recover from day to day. It may take a day or two before I have another go.
Spinning in a low gear, and riding on flat surfaces is my current riding routine (if you call that a routine). I know that if I spin at about 90-100 rpm at a heart rate of about 75% of my maximum (220-age) I will burn the most fat than in any other pedaling range/zone. I have proven this to myself in the past.
If one is not used to it, it can be difficult, not because it is hard on muscles but on cardiovascular system. It requires good breathing and blood flow. I know mine is clogged up a bit, and I need to work up to those pedaling parameters (90rpm@75%maxHR). The main parameter to watch is to stay at 75%MHR (easy to do), then slowly, day by day, increase pedaling rpm to 90-100 while not going over that 75%MHR. Down hills are easier.
I wish to get my legs fit enough to ride the 10 km circuit around town (it has two hills in it).
Then my routine will be to ride daily, adding an extra lap per week for a month, then .....