Tam Coc (or Trang An) and Hoa Lu by Bicycle

I'm hoping to visit Tam Coc (or Trang An) and Hoa Lu by bicycle as a day trip from Hanoi (obviously departing on bike from Ninh Binh). I already have all the info I need on transport between Hanoi and Ninh Binh, as well as info about organized tours along the same route, which I will definitely consider if there is a lot of rain or if I'm not feeling full strength. I do, however, have some questions for anyone who is familiar with this route:

1 - I have read that the Ninh Binh to Tam Coc route is flat, but how about the road to Hoa Lu? Will I be walking up a lot of hills if I don't get a multi-speed bike? (A few are okay.)

2 - I'm planning to visit Tam Coc (or Trang An) in the morning and Hoa Lu in the afternoon b/c every tour I've seen does the opposite. Is there any reason not to reverse the order used by the tours?

3 - I've reviewed all the posts comparing Tam Coc and Trang An but am still undecided. Both are along my planned loop and neither would require any extra biking, so any additional thoughts on where I should do the boat trip? Is either scenic enough from the shore that it'd be worth just stopping by on my bike on my way to/from the other?

4 - Looking at the Google map, there is a concerning bit of road between Trang An and Hoa Lu that is represented by a dotted line. On the (very blurry) satellite image it looks like it might be a washed out bridge. Anyone have recent info on the road between these two sites?

5 - If I end up feeling lazy at the last minute, about how much would it cost to hire a xe om for the day from Ninh Binh?

FYI - Where I live in the southern US is as hot as Vietnam most of the year, and I ride my bike almost daily b/c I don't have a car, so this 20-mile (32k) loop is at least a reasonable physical possibility for me. I'll also be spending many hours on planes and buses several days on either side of this excursion, so I'd really appreciate a chance to use my legs.