From the 91 go south a few miles on the 15 and located along side the 15 at Temescal Canyon Road is Tom’s Farms for fresh fruit, produce, dried fruit, dates, nuts, candies, cheese and wine. Tom’s breakfast and burgers are OK but I stop for a burger with some deep fried cheese curds at the A&W, which can be seen on the west side of the 15, just south of the 91, at Magnolia (the first exit south of the 91). I park and walk inside for a frosty mug of root beer w/ unlimited refills is a perfect drink while taking a long Hot drive. The drive thru does not have frosty mugs.
A&W Root Beer & Long John Silver's
1340 El Sobrante Rd.
Manassero Farms. I was just going to post that.
There's also a fruit stand in Anaheim in Euclid Street near Cerritos Avenue. Not terribly near the 91, but not more than a couple of miles off anyway.
Manassero is much closer to the freeway. The only problem is that if you want to take the FasTrak lane, you will need to backtrack westward from Lakeview, because it starts at the 55 freeway and there are no other entry points.
In addition, there is a fruit stand in the Home Depot shopping centre in Tustin Avenue in Orange (between Taft and Meats), and another called Farmer Boys in Anaheim at the SE corner of Placentia Avenue and State College Boulevard, directly off the 91. It's not a farm stand but more a permanent building with fruit and veg in it.