Hiya, what a worry the night time wondering is. Plus the fact that your sleep is not good either which makes for yet another hard day the next day. Mum also wonders at night and my worst nightmare happened she fell over in the bathroom and broke her shoulder. Its all healed now and she has no memory of it at all. What to do........its a hard one. Mum always goes into the bathroom to rumage around drawers and cupboards, looking at things and moving things around and taking thing to put under her pillow. I used to put a not up in the bathroom saying to go back to bed and I would wake her up in time for daycare and that worked for a few months but no more. It seems nothing is going to stop her, I used to get up and tell her that it was the middle of the night and put her back to bed only to have her get up again in 15 mins. Its such a worry and dangerous but I have stopped trying now and leave her door open so I can hear her but have it in my head now that what happens ..happens. The alarms will let me know she is out of bed but the problem is getting her back and to stay in bed.
These days I just tidy it all up the next day and put the 'under pillow' things back and say nothing.
Since I decided that what will be will be I sleep better and know that if the worst happens I will hear her call out.
I know others have tried side rails on the bed and some even have restraints on for their own safety.
Its hard to know what to do, as side rails and or restraints on my Mum would cause her so much angst and distress that I wont at this stage do that.
If she can still read try the notes (on pretty coloured paper)
good luck with it and lots of hugs.

You can put her mattress on the floor. Biggest issue is you getting down to tend to her. She won't fall far, it is more difficult for her to get up and wander.

Light is important - I turn off all lights and only leave the toilet light on and the door open as a guide. The dark and slight light seem to work wonders.

I got a defuser for Christmas, I would have never thought of getting one for myself, I just add tap water and a few drops of lavender and I have been sleeping much better, Lavender is supposed to be great for sleep.

When my Uncle was alive he did this also. He passed of Alzheimer’s at 95 yrs young. I asked him why he was wondering and he said he didn’t know where he was! I got him a type of salt lamp that flowed a dim orange light. It lit the room enough that he could tell where he was. I also diffused Lavender at bedtime, this helped his sleeping immensely. A little cup of warm milk at bedtime didn’t hurt either. It is a difficult road to walk in their journey, but I did find there were answers If you ask enough questions. I hope this helps.