getting down to water at Etretat

No problem at all. The town is at water level, so you can go from the boardwalk right onto the beach. The hardest part will be to find parking that is close. If I recall correctly, the beach in Etretat is pebbles - so maybe not the easiest to walk on. The town of Fecamp is essentially the same.

The cliffs get big both up and down the coast from both towns. I didn't think the trails along the top of the cliff were difficult for the most part (maybe around the abandoned WWII defenses?). Both towns have a church on the cliff to the north of town. You can park near there and get a look from the top.

There are surely some trails from the top of the cliffs down to the water but, personally, I'd avoid those unless you are following a local who uses them regularly. Trails on cliffs can be tricky, they can appear safe at the start and dead end where the cliff collapsed or set you up for steeper/slipperier sections later on. I used to climb down from the cliffs, with my surfboard, to Black's beach in San Diego when I was a kid but the news always showed tourists either getting stuck or falling and needing to be rescued.

There is no getting down to the water. Etretat is at water level; you climb UP to the cliffs, not down to the water. Or at least we did:
https://janettravels.wordpress.com/2013/01/01/etretat-the-impressionists-had-an-eye-for-a-beautiful-place/
Just park in one of the many lots in the town and enjoy the beach. You do need to be able to climb the cliffs to get a view of the largest of the arches which is not visible from the beach. I don't recall any obvious places to rest on the paths but they are wide in many places so halting should not be an issue. They are rather hazardous as they are along steep cliffs so if not stable safety would be a concern.

As Brad and Janet said, you can walk to the beach from the parking lots. That will essentially put you in between the 2 cliffs. The large rocks are somewhat difficult to walk on. We also drove up a road, from the north, to the church, Chapel Notre Dame de la Garde and pilot memorial which has wonderful views and trails along the cliffs. There is a parking lot. We did not go to the southern cliff.

We were mesmerized and stayed most of the afternoon there hoping for a gorgeous sunset; we had clouds but it did not diminish our enjoyment.

Thanks. My ignorance knows no bounds. lol.
I think I was reading about access to the arch which is not visible from the town beach. At my best I was never a fan of precipitous drops or crumbling trails. I'll pass on that.

There is a sort of grotto that can be reached if you climb the cliffs to the left, where the golf course is. It's fairly easy accès if you bring a cane but the best views are from beach level or on the cliffs I mentioned. There are rudimentary stairs going up the cliffs and a few benches.

I'd skip going to the other cliffs where the church is - it's difficult to accès by car and really nothing up there but à grassy slope and picknickers.

Thé grotto has a pathway and a handrail, but there isn't much of a photo op and no treasure! Try to go on a dry day.

I was entranced by the sound of the waves rolling the pebblles on the beach. An atmospheric addition to the scenery.

Thanks everyone. That sounds really nice Carolyn. I look forward to it.