In th case of a big siege, i think the best is to have extra storage. How? Simple... ships! You dock on the base ships full of stuff and when is necessary, you simple log on those ships and unload the stuff, and hen is safe supplie the base and those ships. I always hated the Barge... every time i saw one i .. damn!!! I even remember escorting one on Kappa ... in 1/2 hour she didn't make it from Delta to 74, and when is was about the midle .. the server went down :-) but ... now ... 30k of Barge can make a good storage room. Those who don't have it .. several 5k transports also help!
And about the trade lanes ... i let the autopilot do all piloting and missed 2! No wories because normaly i usualy make a bit piloting before i enter those trade lanes :-)