I agree. If things don't change, Republicans should concede this race and focus entirely on Nevada and maybe Maryland as possible pick-up opportunities. It's sad because Bennet is definitely very vulnerable.
Maryland? I think Republicans should focus on picking up NV, and defending PA, FL, and OH. Those are their four firewall seats for holding the Senate. If this was a midterm year, and Szeliga was running against Edwards, then maybe Maryland would be competitive, but I don't think so.
What we need to do (if we lose the presidential election, which is looking possible thanks to Donald the RINO) is maintain at least 53 seats in the Senate. That makes the path to 60 in 2018 very, very realistic (probably more likely than not).