Hi there, came back today from my 500k run. This was the itinerary:
Travl Day one (I actually started in MEX)
GU 961 MEX-SAL 6am-9:10am
TA 571 SAL-MGA 1:48pm-2:53
CM 111 MGA-SJO 3:25 - 4:15

Was in Costa Rica for 4 days

Travl day 2:
LR 691 SJO - BOG 10:40am -1:45
AV 076 BOG - CCS 3:45 - 6:35

Travl day 3
VH 500 CCS - MIA 7:20am- 9:30am

ALL the flights were on time actually arrived earlier than scheduled.

Cost: $900.00 (without the flight to MEX)

If you are connecting in MGA, you DONT have to go thru customs or immigr. just transit.!!, the same thing in BOG/SAL