We save our pennies and make 1 trip out of it. Each year we tweak the trip down/back to figure out the best way to transport everything back with us. First year we took the truck with a tarp over it. My mother in law hand her hand out the window holding on the tarp over over an hour as we drove the freeway home. We've since learned from that experience.
We had a minivan for a few years and we'd take out all but 1 seat in that and fill it full of flowers/plants. I mentioned the idea for this trip with a covered U haul trailer and it was SOO nice to just park, fill it and leave.
At 4 dollars a gallon here we opted to take 1 vehicle and just pull the trailer. 30 dollars for the trailer was MUCH cheaper than what it would cost for gas for 2 vehicles. Plus we got more square footage too.
Flower day is something to behold. We can buy a flat (holding 10) 3" potted New Guinea impatients for 9 dollars. 48 plant flats of petunias for 9 dollars. Between the 2 families we buy a dozen hanging baskets. There's a grower there that sells them for 15 dollars a piece. Each basket has stems trailing down easily 6" past the bottom fo the basket and you can get 2 of them for 25 dollars. They are full of million bells, or petunias, fushia plants, doesn't matter they are all that full and at that price. At the nursery its that price for 1 of them. One grower there sells day lilly splits 5 for 5 dollars. He's got easily 20 varieties you can mix and match. Herbs, veggies, so many flowers it will make your head pop. Its a lot to take in. Plus the quality is 2nd to none. Clematis in 3" pots for 5 dollars a vine, heirloom tomato started plants in all the wild varieties you'd have to search the Baker Creek catalog for , trees (like weeping cherry, magnolias, and Japanesse maples), shrubs, prearranged baskets, and cute items like the miniature benches full of flowers, the hen and chicks pouring out of old boots, tons of perenials, its a gardeners paradise.
Plus theres all the regular fair type venders selling elephant ears, nachos, gyros, street musicians, tents upon tents of crafts for sale, there's really nothing quite like it.
So for us its totally worth it. We REALLY go crazy and splurge there because we can't beat the prices or the quality. All the growers are there lined up like at a farmers market with their stock on display. Thats why we get the U haul and why we keep going.