Let's get the easy ones out of the way first. Gore and Colston are starting. Period. Case closed. They're studs, and the first rule of fantasy football is to never bench your studs. The second rule, incidentally, is to NEVER BENCH YOUR STUDS!

Next, let's fill your second spots at each position. Forsett isn't a great option IMO because of the Jones situation and his questionable status. Cartwright was underwhelming in his first start and NO's defense is stingy, so he's out of the running. That leaves LT and Charles, which is a tough debate that we'll table for the time being while we discuss WR's.
OK, so we have Marshall, Johnson, and Crabtree. Johnson is the best receiver, but he also has the worst matchup. Crabtree, conversely, has a good matchup. That said, it's clear that Davis is Smith's favorite target, particularly in the red zone. I don't like messing around with receivers on teams with weak passing offenses unless they're clear #1 options. Marshall has a great matchup and is the unquestioned leader of the Denver receiving corps and has a great matchup to boot. He and CJ will probably catch a similar number of balls and both have great chances to score, but I think you have to play the matchup here and go with Marshall.
Now we've got an RB spot and a FLEX spot to fill and LT, Charles, and CJ left. Due to the matchup with Cincy, I'm starting both RB's here if I'm you. LT may or may not put up good yardage totals, but he'll be good for a score or two against the Browns weak defense and probably get you 12-18 points. Charles is the only show in town for the Chiefs and will get the ball a TON--25+ touches will certainly be good for 100+ yards against Denver's vulnerable run defense, and he'll probably get a score or two as well on his way to 15-20 points. I think CJ will have one of his low-yardage-and-a-score games--maybe something like 4/55/1, which will give you 11.5 points in a non-PPR league. Good, certainly, but LT and Charles have higher upsides. Also, if CJ outscores either, it won't be by enough (maybe 3-4 points) to matter too much; conversely, LT or particularly Charles could potentially outscore CJ by 10 points if CJ has a down game.
So:
RB: Gore
RB: Charles
WR: Colston
WR: Marshall
FLEX: LT
Thanks for the help on mine!