State of MD Inheritance Tax on my Deceased Mothers IRA and Home Sale?
Total value, approx $150,000.?

From what I see you should not have to pay any tax. However, MD is one of few states who separate estate and inheritance. MD:Effective for decedents who die on or after July 1, 2000, property passing to a child or other lineal descendant, spouse of a child or other lineal descendant, spouse, parent, grandparent, stepchild or stepparent, siblings, or a corporation having only certain of these persons as stockholders, is completely exempt from the Maryland inheritance tax. Discussion with a tax attorney would be beneficial.

Agreed; the amount of money in question dictates you seek LOCAL professional tax help, either a CPA or a tax attorney.