Computer systems and methods enable an individual to simulate real estate/financial transactions over time, provide accounting and cash flow management for management of real estate investments, and track property values for rental properties taking into account tenant creditworthiness (tenant credit score) and the like. The computer system calculates a tenant reliability score (TRS) that can be used when an individual real estate investor is contemplating whether to enter into a lease with a tenant. A lower TRS would alert the landlord that the tenant may not be a good risk which would decrease the expected future value of rental property. A simulator preferably incorporates the TRS into cash flow projections such that the investor could compare different potential tenants and. Financial tracking modules enable the real estate investor to track the equity value of his or her real estate investments, cash flow, and to provide data useful for buy/sell decisions.