Terlingua Rental

I'm designing and building a vacation rental home in Terlingua TX. There are no local building codes or restrictions and no local architects or structural engineers. It will be a steel pier and beam foundation, SIP walls (Ext & Int) by Thermasteel, and locally built trusses. There are a few elements of the project that are outside my knowledge base. I need assistance in designing the pier and beam foundation and in recommending and appropriate load carrying beam (preferable hidden) to carry the trusses across and open span where there is no load bearing wall. The house will be on a slope, with the grade ranging from 2' to 6' below the subfloor framing. There will be two sets of trusses. One spanning 23' and the other spanning 14'. The two sets of trusses will butt against one another and rest on a load bearing wall. However, there is one 17' open section without a load bearing wall. I will need to use some sort of beam there, but would prefer for it to be hidden in the attic space -perhaps a fitch plate. I would also like to have engineering stamps for future reference, but those are not strictly required since there are no code or inspection agencies that need to review and approve them. I have attached a preliminary floor plan, and truss plan. Thermasteel will provide me with more detailed plans and information on the walls after they have designed the build package. I would like to know if you could assist me, what type of service you could provide, and the approximate costs.