Most homes listed for sale or lease on Trulia.com, as well as other sites, are represented by a Realtor. You can contact the listing Realtor directly and work around their schedule or have another Realtor show you that home as well as all homes in the areas you want to look in.
This Realtor would be your "Buyers Agent" and will work for you! They can show you any home in the area, regardless of whom it is listed by. This is the best approach as this Realtor can discuss with you your needs and possibly suggest other homes that might meet your parameters. Even more important when it comes to making an offer, assisting you with all the other steps such as inspections and finally be there at closing of your new home.
In the Houston market, the Buyer's Agent receives commissions from the seller or their agent so you don't have to worry about that fee. This would be the best approach if you are a serious buyer.
To find names of sellers, you always can look up the local tax records on the home. In Houston, that would be Harris County, http://www.hcad.org
Don't forget other sites like Switchboard to possibly get the homeowners phone number. If we can help, please let us know.
Bernstein Realty, Inc.