OK, so, that is helpful, but we still need more detail -- what's your take-home, what are your monthly expenses by category, what are the monthly investments, etc.
I did a really quick income tax calculator based on @130K income, two kids, a spouse, and about $1500/mo mortgage interest on primary home (in other words, avoiding the whole issue of income/deductions from the rental properties), and that said you probably would have owed about $12K in federal taxes last year; that's going to be low because it ignores the rental income, but those properties also increase your income as well, so if anything, you'd have more left to spend once you add that money in.
So assuming that you pay about $12K federal taxes, and then you add in your state/local taxes and FICA, that brings you to around say $105-110K net. You're saving about $400/mo on average, plus 1% in the 401(k) for another grand or two. So that means that you're spending what's left over, or around $100K/yr.
If that's close to accurate, then you're pretty much at my initial hypothetical: you'll need about $2.5M to fund just your retirement. The good news is that if you're 15 years away, your current investments should more than get you there by then, IF you have them in the market and the market manages anything near its historic returns.
OR you can stay in real estate. To do that analysis, you'd look at your net profit from all the real estate after costs (including maintenance/vacancy/property taxes/etc.), and subtract that from the $100K/yr you need. So from your numbers below, maybe you're netting $20K/yr. If you want to keep those properties, then you'd still need to cover $80K/yr, which means you need to get your retirement investments up to $2M in 15 years. Or you could look to sell the underperforming rentals and put the money into better-performing units, which would decrease the amount you need in investments to cover the delta.
Whichever option you choose, I'd suggest putting your actual numbers into a retirement calculator to figure out exactly what you need to put away between now and then to reach your target retirement number, and to run it a couple of different ways to figure out whether it's more efficient to sell the rentals or stay in them (note that there are a lot of people here who seem to enjoy doing that for people, but they would need a ton more detail on the expenses and investments and taxes and all that in order to do so). But the key is that this is your first step: you must figure out what you need for retirement first, because you have no fallback for that.
Once you are confident you have a plan to cover your retirement, you can look at what's left and make a plan for college and boat.
