So you create a government, that by its mere whim can decide to grant/take away billions of dollars from individual companies (See Tesla vs. Coal) and then you expect companies not to want to have a say in the outcome. The easy solution to the outside influence problem is a less intrusive government that doesn't make it worth the money to spend on politicians. If the government had less influence on the economic outcomes of people and companies - people and companies would spend less money on getting the outcomes that they want.
Lets start with a mandate that ALL congress critters must go into a sealed room with a pencil, calculator and a land line that only dials the IRS help line (where they can wait in the queue). They get to do their annual taxes, turn them in and have a super audit with published results (ok, lets say %accurate). Hopefully this will lead very quickly to a new tax code that is significantly simpler without all of the carve outs, and fancy working that can be misinterpreted.
Next lets start with regulations - make congress responsible for following all of the laws that they pass, lets start with minimum wage - Yes interns should be paid at least the minimum wage.