Surfside Beach is in Brazoria County. It's only about 52 miles from Sienna if you take FM 521 to Highway 288 through Lake Jackson. It's an easy drive without much traffic and its where the kids from Ridge Point often go when they want to hang out at the Beach. Back at Dulles in the mid 1980's I remember going there so its funny to me when my boys go. It's actally only a couple of miles long and you'll drive right through it if you're not paying attention. I was recently there and it was very clean & had no seaweed at all. I've read seaweed is seasonal (and good for the dunes) but I don't understand how sometimes during the summer it's so bad and sometimes there is none at all. Surfside is a good option if you are wanting a beach close by that is not crowded. You'll want to pack an ice chest of food & drinks, as there are not many stores or restaurants once you get there. As far as rentals, there are a few but those are limited. If you drive a bit further you'll come to Point West which is a newer, larger community with lots of options for renting. The further East you go the more houses, stores & restaurants you'll find but it also gets a bit more crowded. For just a day trip Surfside is a good option.