This is a map I put down on paper for my own use a while back. I find it useful at times so I pulled out Gimp and whipped up a quick digital version to share with everyone. The map shows the main hi-sec trade hubs and the number of hi-sec jumps it takes to travel between them.
I'm not real big on moving stock between hubs but when I do I usually use Red Frog Freight to move stock for me rather than move it myself. With RFF most of my contracts get delivered within 24 hours, shipments between major hubs usually take less than 12 hours and shipments originating from or being delivered to Jita often only take an hour or two.
There are 2 main trade routes I use far more often than others.
Jita is the monster trade hub with a larger market and more pilots docked and active than all other major trade hubs combined. Amarr is the next largest. Looking at the star map Jita and Amarr are quite far apart in absolute distance. One might assume the hisec jump route from Jita to Amarr is a long one with a lot of jumps but it's actually one of the shorter routes at just 9 jumps. It's a very busy route since Amarr is both closer to Jita than any of the other major hubs and the next largest major hub (after Jita) too.
Dodixie > Hek > Rens is just 14 jumps between 3 major hubs. It often makes sense to bundle everything up in Jita and send it to Dodixie first. Post some on Dodixie, send the rest to Hek, post more there and forward whatever's left to Rens. It will take longer routing courier contracts that way but in the end it'll save you 30 jumps over sending contracts directly from Jita to each of Dodixie, Hek and Rens.