Climbing stairs/steps at Mont St. Michel?

It's been quite a while since I was there but, as I recall, there is not one long staircase. The climb winds around and there are lots of places to stop and rest (and take photos). Just plan to take your time.

EDIT: I agree with Tom below, it's mostly just an uphill paved path that I remember with occasional stairs, especially at the end.

I might be remembering this incorrectly, but I recall it mostly consisting of a winding uphill path, with the stairs only towards the end.

There are some "longish" stairways (as in maybe 3 flights together) with landings etc. There are also places to stop and lots of people stop on the steps to take a break. If you are reasonably fit (and it sounds like you are) I think it is pretty doable for you. There are (a guesstimate) less than 200 steps up to the Monastery itself. There are some steps inside the Monastery and most of us opted to go around the walls as well. More steps there. However, it is pretty broken up (some steps, some flat, lots of places to stop, look out, even shop/eat etc.)

Lots of steep street, lots of steps, but also it is easy to step aside and sit on a wall or at least pause while people go by you. If you have problems with steps it is not a treat as there are a lot of steps. Towards the end of this entry in my photo journal there are pictures of the steps near the abbey and in the abbey so you can get a sense of what they look like.
https://janettravels.wordpress.com/2014/01/21/mont-st-michel-is-that-a-real-place/
We were there in late October and so it was not crowded. I imagine it is more daunting when it is wall to wall people on those steps.

Not knowing how bad your back bothers you, it's hard to say whether you can or can't do it. It can be challenging because flat isn't the same as a hill or steps. It's a slightly different use of your muscles. Can you find someplace hilly to do a little walking or do some stair climbing before you go? It might help you gauge your ability (and increase your capacity).

The Mont St Michel site says this:
There are no steps between the car parks and the site. The shuttle stops 400 m from the entrance to the Mont and the main street is 200 m long, mostly up hill. At the top of the main street, starts the "Grand Degre" stairs (350 steps) which leads to the Abbey.

There are varied and interesting things to see everywhere on the Mont, so it's not like a boring endurance test to get to one particular place. I'm not clear about places to rest but there's a chapel about half way up the main street where you could sit and you can always go into a restaurant. If there any ledges along the main street, there are likely to be people perched on them.
A big attraction is walking along the ramparts, pretty level themselves, but accessed via stairs.
So, lots of up (and down) hill walking and lots of steps, but you can take your time. There are other streets and stairs and passageways which make it fun to explore the town and once again, plenty to see and no reason to hurry.

Went with hubby who has a bad knee and my 70 year old Mom. I'm not very fit but I can do stairs if I need to as we did many castles that trip too. The bad part was I hurt my back pulled a muscle unloading the suitcases from the car the 2nd day of our trip.

We only made it to the Chapel a little more than 1/2 way up. We got there a little later in the November afternoon than I wanted so it was getting dark and we were tired. The angle of the path made it very hard. We did some shopping, took lots of pictures and said ENOUGH.....We never made it to the top but did not feel slighted either.

BTW, the food on the mont was not very good. Had the worst meal there. Bring or buy sandwiches. We did not have the budget for 50 euro omelettes LOL

Note that there are two "routes" through the town, to the abbey. One is the steep medieval street, with some steps, the other is the "wall" route, which is more like multiple staircases separated by smoother (than the stone medieval street) and less steep walkways. I'm not saying it's "easier", it's the same total elevation, of course. But it's more formal, better distance views, less medieval town scenery.

I found one of the difficult things about the steps up to and within the Abbey was the lack of handrails. When I was there on Rick's Paris and Heart of France tour last Fall most of us went to the 6:50A chanted prayer service of Lauds. It was rainy, it was dark and I found the steps quite slick so wanted a rail to help with balance. There was a large rope in the center for the first part in the Abbey and then nothing that could be detected with no lights the rest of the way.

Walking along the walls is neat but you do need to climb up steps to get to the wall entrances.

I would say go, do what is comfortable for you but don't feel bad if you don't make it to the top. I felt the view from the causeway was actually more impressive than the sights inside. Most of the main street is lined with shops and restaurants so plenty of places to get away from the stairs.

I've always read that the food is bad but we had dinner at a restaurant in a hotel near the abbey and it was both reasonable and reasonably good -- traditional 3 course French menu.

Wow, thank you all so much for the information. With your input, I am pretty sure that I can manage the climb. Hopefully, it will work up my appetite to allow for the dinner meal to taste wonderful! ;)

My Mom was in her 70's and had had a hip replacement when she climbed MSM, and believe me, she didn't walk even a mile a day. There were many places to rest and the walk way is wide enough that you can go your own speed and not worry about holding up other people. As I recall, the way up was a little steeper than the way down and we were surprised to find ourselves at the bottom so quickly. It was one of the highlights of our trip and worth the effort.

Wow, I was surprised to read there were 300 steps..... I guessestimated less than 200 Oh well, in any event, I've had both hips replaced but do walk 4.5-7 miles 3-5 times a week with a few hills. When I went, I didn't stop and rest at all. However, everyone will have their own pace. Some young fit teens/adults will bound up two steps at a time while other people will stop every 10. No right way to do it. The beauty is, wherever you stop to rest.... just look around, you are in a gorgeous spot. So relax and go for it. Even if you don't get in (and I kind of suspect you'll make it) you'll have a blast on the island. As a ps. because our guide warned us of generally over-priced or bad food I did not eat there. However, he told us about a restaurant that served the salted lamb (supposedly sheep were naturally salted by the sea air!). Two of the gourmands on our tour did eat there. They said it was expensive but absolutely worth it.