I agree with the previous posters who said that the Mass is the most important part of your mother's wishes, because it is religiously motivated. Skimp on the flowers and the casket, and skip the funeral home facilities entirely, but keep the religious service that she requested.
Just FYI, it is possible in many jurisdictions to rent caskets for situations where the deceased with be cremated after the service. (The casket liner is made out of waterproofed chipboard; it is removed after the service.)
The Church itself will not charge you very much for the use of the sanctuary for a Mass. You can usually have a brief viewing in the church vestibule before the service as long as it does not conflict with scheduled Mass times.
Those who have said that a Requiem Mass cannot be said in a funeral home chapel are correct. A priest can conduct a prayer service there, but it would not be an actual Mass (with Communion offered for the attendees).
Also, it is traditional for a Priest to lead the mourners in praying the Rosary the night before the funeral. These days that is usually done at the funeral home viewing in the presence of the deceased, but it can also be done in a private residence with only the mourners present.
PS: In re: the question of embalming: it is not necessary if the deceased is to be cremated, but some jurisdictions require that it be done if there is a burial.
BTW, a note about VA cemetaries. If a veteran is buried in a VA cemetary, a later-deceased spouse may share the grave. This is especially simple if the spouse is cremated. The name is placed on the back of the veteran's grave marker. (In some cases the spouse can be buried there even if the veteran was not: see
http://www.cem.va.gov/bbene/eligible.asp for the detailed eligibility rules.)