The House and Senate Map don't matter in 2018, or even 2020. This is the only map that does.
There is no win condition, especially in 2018, for either party, that doesn't include locking down critical swing states in preparation for 2020 Census redistricting, that takes effect in 2022.
If Republicans Triumph here, they will lock in the 2020s as they did the 2010s. starting with 2012. If Democrats triumph, they'll reverse it.
It Republicans win the House and Senate, but lose Florida, Ohio, Michigan, Maine, Nevada, Wisconsin, Illinois and New Mexico governorships to Demcorats, they'll find themselves wiped out in the 2022 midterms and 2024 Presidential Election. It will be a catastrophe for them sandwiched between a short-term stay of execution. But they'd be a dead party walking, going into 2022.
If Democrats win the House and Senate, but manage to lose at least some of those key states, they'll enjoy nothing but misery in the 2020s. Exact same thing. Republicans will extend their post-2010 redistricting advantage.
Either way, focusing on who controls the House and Senate after their 2018 midterm is incredibly shortsighted. It basically doesn't matter. Why do I say this? Because unless Democrats can somehow get a supermajority in the Senate - and they won't any time soon - the only budgets that will be passed, which is to say, the only way anything gets done, will be like the 2 year deal signed by Obama after being passed by Republicans in late 2015, and the template for the 2018 budget that is likely to be passed. The EXACT same constraints that exist on Republicans exist on Democrats. The far left won't get anymore of what it likes than the far right, so the only budget that can pass has to appeal to both parties.
In other word,s get to know and love the 2 year deal budget blueprint. It's what budgets will look like for many, many years to come, regardless of which party controls which house of Congress.
Everything else? Minutiae. People can talk about regulations or some minor policy. I prefer to worry about how $4 trillion in taxpayer dollars are being spent. That means budget. And unless something dramatically changes, no matter who is President, we know exactly what that budget will look like plus or minus five percent for years to come.