Samu is vital to Practice. In fact, Samu --IS-- "working Zazen"!
I strongly encourage community volunteer work as Samu, for those who can make the time. I have not been too insistent on people doing "Samu" work practice at Treeleaf, but I think I should crack the whip a little. If someone will do community volunteer work, preferably, it should be hands on actually helping people in need like the sick or elderly or kids in need (not just folding envelopes)
However, for those already loaded with work and family obligations with absolutely no time for anything else, an intentional commitment to non-do some of those activities is "Samu" practice.
For example, if your Samu is work at home to support others in your family, I believe it is important that the work there you pick for daily Samu should be something you mentally resist a little. If you hate washing the dishes or washing the bathroom in your house, that is excellent Samu ... because a large part of our practice is, of course, learning to drop resistance and drop "likes" and "dislikes", and just to be present with how things are. Samu does not have to be something outside of our normal life though, and if you are busy with a job in the office or factory or taking care of home, well, just pick something in those places that you mentally resist. Samu should perhaps last an half hour or hour at least (though, truly, there is no time limit on Samu ... all can be seen as Samu), so for overworked people, you can select things within your existing duties at home and work. Excellent Samu! If we clean the floors, for example, silence is usually an important part of it. Also, dropping likes and dislikes: We wash the floor DILIGENTLY and CAREFULLY, but without any thought of "clean" "unclean" or a goal. Tricky, but it can be done on the "simultaneously true" channels we practice here.
We could have a group in which people discuss Samu and support each other.
Now ... as to
Dana, the practice of selfless giving ... putting something in the monk's bowl ...
I do not accept any "Dana" financial contributions for Treeleaf, as we now have sufficient resources for what we are doing. However, I do encourage people to make financial donations to charities that help folks, e.g., feeding the poor, finding a cure for a disease. Both donations and Samu work should be a bit beyond the point where it starts to hurt.