Thus, unlike you, I don't live in Kansas, but so long as Pat Roberts or Jerry Moran get to vote on national laws, national budgets and national taxes, I and each and every other American have standing to criticize or support either of them and you have the same rights as to 98 non-Kansan Senators. America, it's a great country!
All that having been said, we don't ask much of a person who seeks to serve in the Senate: American citizenship; at least 30 years of age and a residence in the state he or she seeks to represent. Since Roberts has been in Congress or the Senate since 1980, I would suppose he has met the age requirement and now seeks a fourth term in the Senate. I have never heard any question as to his American citizenship.
OTOH, there is that pesky residence requirement. Apparently Roberts is such a tightwad with his own money that he won't rent a studio apartment or even a bedroom in Kansas. Not the first senator or congresscritter to do so and probably not the last.
As to age, 77 years old is a good time to call it quits and he should. His career is not THAT memorable in any event. If his opponent is supported by Mark Levin, that's good enough for me.
Senator Roberts long has owned a home in Dodge City. It currently has a tenant; he also pays rent at a residence where he stays when he is in Dodge City. He pays Kansas state tax and property tax. There are those pesky facts.