Good luck, wish I could join you but I am now married and living in Finland. I cycled from canada to equador back in 95 - 97. It was an amazing journey and I am sure you will have one too.For me Colombia was the best part of that trip in regard to the cycling.I was so worried about Colombia as I took the old dosco boat from Colon to Cartegena.All the nagative press you here about the place. But it turned out to be the most cyclist friendly counties in all of my trip.The police and military road blocks always stopped me, but never to hassle or rob me, only to ask me all the usual questions about the bike and the journey and to shake my hand and wish me good luck.And they always told me about some very lovely blonde female german who was always 2 hours - 2 days ahead of me.I never met her - I think they may have invented her to spur me on ;-)
Ofetn in bars and local diners I would go to pay my bill and find that someone else already had.
Cycling is a big sport in colobia , anyone who has the money is out on their shiny racing bikes at the weekend in their Cafe de Colobia Tour de France shirts. I honestly think that as a cyclist in Colombia you get a lot more love and respect than if you are backpacking.
Lisyen to local advice - if someone tells you that this road is unsfafe due to recent insurgent activity , but the other road is fine - believe them.
I know my trip there was 13 years ago now and i understand the situation with the drug gangs might be more dangerous, but I hope you find this information useful.
As for crossing the darien - I took the big disco boat on the way south but coming back north a year later it did not run.So took small speedboats ( paid a bit extra for bike ) from Turbo ( colombia ) to Arcandi and Capagana ? ( both still Colombia ). camped on beach no problem at Capagana ( did have basic hotal but full of mosquitos ) then the next day paid a local fisherman about $ 5 to take me and bike around a few headlands ( in a dangerously small panga boat ) to Puerto Obildia ? in Panama. It was no problem then with customs duties there, just had to check out of Colobia from Turbo, not the smaller later villages.Check for more up to date info.
camped on the airstrip in Obildia for the night and maanged to get out of the way in time for the morning arrival which flew me back to Panama city in a 6 seater plane ( with bike ) for about $50. Flting over the jungle is amazing - it looks just like looking down upon brocoli in the supermarket - there are even little patches of purple sprouting ;-)
At the time there was also I believe a weekly boat heading north from Puerto Obildia along the caribe coast to the San Blas Islands.
A tip for when you are climbing thru the Andes in south Colombia ( and other big hills on the way ). I got this from watching the kids playing on their go -carts and young adults collecting firewood from higher elevations. When one of the many slow moving big trucks are just about to drive past you, a quick spurt of enegy on the pedals and you can grab onto the back of the truck and get afree ride uphill. Better not try this if you are a novice cyclist though.At best you well get a lungfull of exhaust and at worst killed under a big truck.
hope you find someone to travel with and all good luck for you.
happy to provide any more info if you need it,
best wishes
jim fullwood.