I am gravity bleeding the brakes on a Myco trailer, after replacing all the calipers and rotors.
I tilted the nose of the trailer pretty high, and opened the rear brake bleeder valves, air came out, followed by a steady drip every two or three seconds. Closed the rear valves, opened the fronts, same thing, steady drip every two or three seconds. I used about a half pint or slightly more of fluid in the whole process.
Do you think this is sufficient? I don't have access to a power bleeder, and I don't know how to easily pump the master cylinder myself.
Any other tips?
Thanks in advance.

Disable the reverse lock out and try backing it up.
as long as all the air is out of the lines you should be good to go.

Better get some help. That's a two man job.

I bought a hand held vaccum pump from AutoZone that is suppose to be good for bleeding brakes also. It appears as you fill the master cyl up, then attach the pump to the bleeder screw, pump up creating a vacuum in the spare bottle, open bleeder, and WA LA. Haven't tried it, so...........
Think it was around $40-$50????

I've always done it the hard way. Used my truck to bleed it.

Try those "Speed Bleeders". Makes it into a one man job. You just crack open each bleeder and it forces out all the air. A one-way check valve prevents air from entering the line. They are about $12 / pair. Available from any Motormite (HELP!) retailer.

i found this to work well for a one man show, but a block of wood behind of and in front of the trailer tire, hook up the truck to the trailer then move shifter from reverse to forward a couple times leave in reverse with parking brake set then get out and bleed one wheel, it goes pretty quick
Mark

Just like H2XMark said. Instead of pumping the brakes like in a vehicle. You block the wheels of the trailer(front and back so it can't move) and pump the trailer with the tow vehicle. Done it by myself on numerous trailers and no problem.

The "proper" way is to pressurize the system either by applying air pressure or pumping it up somehow.
But I'll tell ya, I did the same as you when I replaced the rear brakes and wheel cylinders on my old truck. I left the first bleeder open while I went to find a drip pan. When I returned the fluid was running out like mad. Did that to the other side. When finished I got my neighbor to pump the peddle and hold pressure while I cracked the bleeder. No air came out. Tried the other side, same, no air.
So I'd say that gravity bleeding works just fine.

I installed the reciever insert with the ball in the coupler, then used it to pump the master cylinder. I found that by stepping down on it with my foot I was able to get the job done. It is a two man job doing it this way, though.

I have also used the vacuum pumps sold at Autozone to bleed brakes. Works every time.