Sanders told the Post, “I will be vigorously in opposition, and I will make that very clear." He said other senators, including Elizabeth Warren, are planning legislation to create a $15 federal minimum wage, free public college, and to aggressively address climate change. The whole article is worth reading.
While the orange neofascist could still win, it's highly unlikely, which means progressives should begin turning their attention to pushing their party as far toward democratic socialism as possible. You do that by electing Hillary Clinton, electing as many Democrats as possible, and then pressuring her to eschew the centrist/bankster/neocon stuff and to follow through on the making the historic Democratic Party platform (which includes pot legalization!) a reality.