Mate with leg problems needs a hotel with bath. The 'bath' he booked in Silver River is a shower stall about 2" deep.

Anyone got any tips in the $40-80 range?

From my own experiences in SEA, if there is a proper bathtub it will probably be too filthy for a sane person to want to immerse themselves in, and even if you request that the cleaning lady person do a thorough job (and provide a generous tip) the cleanliness would still be wanting. I which case you have to get hold of some cleanser and scrub the tub yourself, which may be difficult for someone with leg problems.

Also there is the matter of sufficient hot water (for me, lukewarm baths just don't cut it).

But I don't travel at the US$50+ hotel level

My best bathtub experience in the region was in Indonesia, I found a hotel that was in the $150 range, it was off-season, the town was dead and the place was empty, they gave me a weekday rate of $20/night (plus about $10/night in various documented taxes). It was like being in a decent hotel in a modern country. A lot of tub time, was even able to watch tv while soaking -- ain't that the life!

I have encountered full baths with quite usable bathtubs many times in PP hotels but unfortunately haven't kept records, and this can be hard to determine from a hotel website.

One place that i am positive of as I often stay there is Embassy Place Apartments. These are serviced apartments but will rent by the night if they have open units which they usually do. They have their own website and also list in Agoda. Fully furnished and equipped, daily maid service, very nice garden and pool, but but no room service (easy enough to order in from many restaurants though). Good location right at Independence Monument on Norodom.

The one thing to be careful of is that some apartments at Embassy Place are walk-ups, if he can't manage stairs may want to make sure he gets a ground floor one. I think the ground floor units tend to be 2 bedrooms while the one bedrooms are on upper floors but cal email them and ask.

There are also regular hotels with nice baths, and if able to go up to $80/night, will have ample choice, the problem is the identify them.