From a numbers standpoint, the highest use of this capital is to sell and buy another investment, or even just invest in the markets. Even if she just pays the capital gains tax - likely 15%-16% effective unless she has a very high income - it shouldn't be very hard to beat the return she is getting on that true equity. 1031 is not even necessary to justify selling. Here's the quick math:
$1,300,000 (Sale Price) - $130,000 (Sales costs 10% of sale price conservatively) = $1,170,000 net
$1,170,000 (net sale proceeds) - $550,000 (cost basis assuming no improvements) = $620,000 Capital Gains
$620,000 (Gross Cap Gains) - $250,000 (Cap Gains waived for primary res) = $370,000 taxable cap gains
$370,000 x 0.15 = $55,500 cap gains taxes owed
$620,000 (capital gains not including original equity in the home from downpayment and principal payments over 5 years) - $55,500 (cap gains tax) = $565,000
That $565,000 number is the apples to apples number that you want to make sure you're getting the best return you can from. $2,500 monthly rent (not subtracting monthly expenses and mortgage payments yet) is $30,000 annually which is 5.3% return. Assuming at least 50% of the rent is going to expenses and mortgage payment, now she's making 2.65% on her money. She can get that in a high yield savings account. No hassle, 100% liquid.
Now factor in the equity she had at the beginning, the option of using a 1031 exchange, and intelligently investing the proceeds and there is a TON of room to improve the return on this capital!