Let's try to project the future as far in advance and future elections based on current trends.
2016:
Former Secretary of State Hillary Rodham Clinton (D)-New York/Secretary of Housing and Urban Development Julian Castro (D)-Texas 343
Businessman Donald Trump (R)-New York/Congressman Steve King (R)-Iowa 195
Senate: Dems +7
House: Dems +13
Despite unprecedented attempts to prevent Donald Trump from gaining the GOP nomination he managed to build up a comfortable lead in delegates with Kasich and Rubio dividing the establishment vote and only Ted Cruz putting up opposition on the right. On the Democratic side Bernie Sanders managed to put up a respectable showing and won New Hampshire. Though Hillary Clinton ended up clinching the nomination rather early, Sanders remained in the race to push his message.
Very few Republicans were willing to run on a ticket with Trump. He offered the VP slot to Sandoval, Rubio, Kasich, Bransted and Cruz, all of whom turned him down before eventually settling on congressman Steve King of Iowa. Much of the GOP establishment ignored Trump and he ran a largely self-financed campaign with the Koch Brothers opting to bankroll Gary Johnson and Wall Street pouring billions into the Hillary Clinton campaign. On the Democratic side, many Sanders supporters flocked to the banner of Jill Stein though the prospect of a Trump presidency combined with Sanders endorsement of Clinton kept many reluctantly in the Democratic camp.
Coming out of the GOP convention the election was relatively close. However several high profile hate crimes and frequent incidents of violence at Trump rallies which he refused to condemn led to his candidacy sinking and many congressional candidates in competitive distracts refused to appear with him. It also provided the Democrats with unprecedented opportunities for attack ads and GOTV efforts. Although many had suspected that Trump would be able to pick off several Midwestern states early in the election the map remained unchanged from 2012 with the addition of Arizona, largely due to Hillary winning over 95% of the Hispanic vote at an unprecedented rate, while Gabrielle Giffords pulled off an upset in the senate race. Shortly after the election, in response to militias posing outside polling places and attempting to prevent people from voting the Justice Department filed several lawsuits for civil rights intimidation.