Your trade route only needs to pass through the area of effect. However, I wouldn't get too crazy with building econ star bases just to bump trade.

Firstly, trade routes can, and do change frequently during the course of a game for various reasons. Your trading partner can become your enemy, the planet your route goes to is captured by another civ, or simply more profitable routes turn up. I rarely am trading with the same planets that my first trade routes went to at the beginning of the game.

Second, have you calculated the number of mouse-clicks required to build a fully upgraded starbase? For sure, and for certain, your starbases will become targets during times when you are at war, so you will need to put hefty defenses on them. It takes roughly 10 mouse clicks for each module...from selecting the planet to build a constructor, to opening the build list to confirming your selection, then closing the dialogue, then selecting the planet again when it's done, launching it, then selecting the starbase to be upgraded, to confirming which module you want to install.....

Now considering that a fully upgraded starbase can have something like 61 modules (someone correct me if that number is wrong), that's 600 or more mouse clicks for EACH starbase. It leads one to think someone at Stardock held interest in Logitech

I never understood why they didn't simply handle constructors like a planetary upgrade; you select the spot where you wish to build a starbase, you then select what modules you wish to install, you pay for them (which you do anyway in the current system) and are given a time to completion. Simple and user friendly. For galactic resources, you need only the initial constructor to stake your claim on a resource. After that, the above system would apply.

In my own games, I might have as many as 20 or 30 starbases of all kinds, so that's literally thousands of mouse-clicks. My arm and wrist go numb, to say nothing of the wear-and-tear on my mouse. Building constructor after constructor is THE most annoying feature in the game, for me. It's the reason I stopped building the military version and go only with econ bases. Econs will benefit me every turn regardless of expansion, while military bases are used only in times of war, and usually become left in rear areas as my empire expands, and hence useless. Not worth the effort, IMHO.

Yeah...I really don't care much for the way this feature was designed  

In using my system, you do have a time factor involved, not just money. Each module has not only a cost, but a time-to-build figure associated with it. If you order up multiple modules they get placed in a queue just like planetary improvements. Modules do not become functional until their build time is completed. This prevents getting a fully functional star base with all the add-ons all at once.

I would say that I spend 1/3 to 1/2 of my game time building and moving constructors. It's time wasted, IMHO, and it certainly detracts from a very fine game, for me. 

Although, do they have the option of autobuilding starbases?

Everyone to their own style, I guess. Have to disagree about a fully upgraded starbase being easy pickings. I've had one destroy outright, a pirate fleet complete with battleships that would've been a serious load to handle for even my best fleets, at the time (and we're talking better than halfway down the weapons tech-tree). And certainly any galactic resource mines you have will become immediate targets during wartime, and will have to be defended. With a fully upgraded base, I don't bother with a covering fleet...they can take care of themselves, for the most part.

And please correct me if I'm wrong, but if you wish to get full benefit from an econ starbase, you need 10 constructors minimum, yes? Initial, then 10/20/30 boost to trade, and six for the mil/soc/res boosts (and of course I'm referring to bases within your own territories). With my style of play, I might have 30 or more econ + resource bases. Even with the minimal number of constructors, that's still hundreds of mouse-clicks when you add in the ones required for opening the purchase screen, choosing which unit (I always have several speeds depending on how far they have to go), closing the screen, etc. All unnecessary, IMHO.

Regardless, I still see the UI, as I've described it, being far more user-friendly than even way-points, and such. How could it be any simpler? Point, click, pick from a list, pay....and forget about it until more modules become available.