I agree if you are looking to invest locally the best is to go to a local real estate club. You can get advice and meet people that can help you close on deals you want (agents, insurance, title, etc.). Being conservative I would recommend investing in rentals in another state. I have been looking in our area and it's more difficult to find something that will cash flow than less expensive states so you are hoping on appreciation. If you are a long time BP lurker you probably see many articles where you could go. (GA, FL, TN, TX, etc.) At the club you will probably find others investing in other states too and you can partner with them or help get contacts to work with to find a place.
But with your plan it's pretty easy to back into goals to get to what you want. I like to break things down and simplify then its much easy to be focused and know what you are after. Using 3% annual inflation on $60-75K it will be $122-$152K in 25 years when you retire at 59. So break that in small chunks to get there. You are going to have property management fees, assume some vacancy, taxes, insurance, capex, and maintenance even if the houses are paid for. I think 50% of the rent is very conservative for all those expenses what I have heard. Let's assume the 1% cash flow rule. You need around $2M to $2.5M in real estate. For easy math let's use $100K valued houses and $1000 rent (1% rule). If you buy 20 houses or 25 houses, that will get you there. At 20 houses @ $100K thats $2M in real estate and $240K in annual rents minus the 50% in expenses, so a net $120K. At 25 houses @ $100K thats $2.5M in real estate and $300K in annual rents minus the 50% in expenses, so a net $150K. So an easy goal if you buy 1 house a year for the 25 years until you retire at $100K, you can make it there pretty easy. At the income you can probably save the 20% or more down for that each year. Maybe the 50% expense is conservative so you might get even more. Also I'm not assuming appreciation but ideally there would be some. It will probably depend on your loan terms but a few houses will hopefully be paid off or close to at that point.
Also keep putting away your 401k and roth. I like those because you are putting that money away and lowering your taxable income and hopefully where you work you get a match. This also will give you multiple streams of income to diversify so you have real estate and the stock market, and potentially social security if its still around and you have a regular w2 job.
