Sorry, not sure but I went early/mid afternoon and it was open. Rather hard to find. I had to ring a bell for entry, like at a private residence.

The admission fee was €3 each

Ulgowy 4 zl...ale bilet do Muzeum na Pawiaku jest jednocześnie biletem wstępu do Muzeum na Szucha, nie trzeba w dodatku odwiedzic tych dwóch obiektow jednego dnia.

My hotel was nearby so I just walked. The bus system in Warsaw is very efficient though so I'd recommend you investigate that.

A taxi ís incredibly cheap from anywhere in the city centre but we walked on this occasion as it was only a 10-15 min stroll if you are able. We used a taxi quite a lot for many of the sight seeing visits and the service was very good. There are 3 or 4 well known, respectable companies which seem to circle the city all day and half the night. If it it hasn't got a meter which you can see, don't get in it is my best advice. If you are in a hotel, you can always ask them to order you a taxi. Hope the helps.