What do you mean you have no power to the cab? No lights? No instruments? no accessories? all of the above? Or is it you are not getting any results when you turn the key, as in the engine does not turn over, but you have dome lights and accessories.
If you do not have *any* power whatsoever, battery or battery cable/ ground is the first place to look.
If it is the truck isn't turning over but you have lights, check the battery with a load test (you can have autozone or oreilly's test them for free) check the connections to the starter, ground, solenoid on the fender. check the solenoid on the fender, check the starter. (since you replaced the starter and solenoid already, we can assume that has been ruled out as an issue, but make sure you didn't get a bad one.) after you have ruled out those, look at the ignition switch.
AJ