One thing that would possible be interesting to see would be to beat Star Control II without ever visiting the starbase. I do not know whether it is possible, but according to the source code (at least UQM, but probably original SC2 as well), at least the game is prepared for the event that it happens. For instance, once you equip the Sa-Matra detonator (the Chmmr-empowered Utwig bomb), you will be teleported back to Earth rather than to the Starbase.
Minerals will be useless. You will have to collect biodata and rely on the Melnorme traders. Fwiffo (the lone Spathi captain on Pluto) will become invaluable in fending off the rogue Slylandro probes, which you cannot evade with your slow SIS ship. (The Melnorme do take your turning/thrusting jets if you cannot pay for fuel, but they will not sell you even one.)
Your fuel tank will only store 60 units of fuel (you cannot build more tanks or even the bigger tanks disclosed by the Melnorme without visiting the starbase), so you will need to plan your excursions very carefully and to rely on the Melnorme traders on tight intervals. You can also buy fuel from the Druuge, but it will cost you crew, which is not easy to come up with.
Also, the only way to recover lost crew is by transferring them from ships you receive as a gift. This way, it is theoretically possible to purchase Druuge's expensive gifts. Your SIS ship can only store 50 crew, since you cannot build new crew pods. Note that once your fleet is full, you cannot receive more gift ships until you intentionally destroy some of your fleet. Note that Pkunk ships can regenerate crew if they are destroyed in a battle.
This will easily be at least a 2-hour or 3-hour movie, but it will include many things that are interesting to see that are completely omitted in the current TAS.
For reiteration, here is the list of things the Melnorme do sell:
-- Fuel. You can buy fuel any time. 1 credit per unit of fuel. Even if you run out of fuel in deep space, they will come and sell you fuel; it will just cost you an arm and a leg; and if you don't have those, they will donate invest some for you. One of those "arms and legs" is your planet lander, which you cannot get a replacement for without visiting the Starbase. So you do need credits. You do have a very miniscule chance (about 0.25^256) of keeping your stuff though.
-- Information. Information is sold about current events, about alien races, and about history. Since no information advances the plot, they will never be seen in a TAS. All information pieces cost 75 credits per item.
-- Technology. All technology cost 150 credits per piece, and you cannot purchase tech N without purchasing tech N-1 first. Technically none is required in a TAS, but Tech 2 and Tech 7 have potential of making the TAS faster.
---- Tech 1: Blaster weapon SCHEMA.
---- Tech 2: Faster landers. Which they will not sell unless you bought Tech 1.
---- Tech 3: Antimissile defense SCHEMA. Will not sell unless you bought Tech 2.
---- Tech 4: Lander shields against biology. Will not sell unless you bought Tech 3.
---- Tech 5: Improved lander cargo capacity. Will not sell unless you bought Tech 4.
---- Tech 6: Larger fuel tank SCHEMA. Will not sell unless you bought Tech 5.
---- Tech 7: Improved lander stunners. Will not sell unless you bought Tech 6.
---- Tech 8: Lander shields against earthquakes. Will not sell unless you bought Tech 7.
---- Tech 9: Tracking system SCHEMA. Will not sell unless you bought Tech 8.
---- Tech 10: Lander shields against lightning. Will not sell unless you bought Tech 9.
---- Tech 11: Lander shields against fire. Will not sell unless you bought 10.
---- Tech 12: Cannon weapon SCHEMA. Will not sell unless you bought 11.
---- Tech 13: Shiva furnace SCHEMA. Will not sell unless you bought 12.
All SCHEMAs are completely useless: Credits will be paid, but you cannot build any of them without visiting Starbase.
Your space battles will be all done with ships that you acquire on-visit; you can never build new ships. That means no Chmmr, no Orz, no Arilou. You do get:
-- One Spathi ship with just one crew member (Fwiffo on Pluto)
-- Four Pkunk ships (repeated as many times as you want, but require at least 1-gameday intervals)
-- Druuge ships (one per every 100 crew you sell to slavery Since your SIS ship can only store 50 crew, this is impossible. Six ships if you pick up and sell the Shofixti maidens)
-- Four Umgah ships (after de-zombification) Impossible, because you're given a battle you cannot escape nor win.
-- Four Supox ships (repeat as often as you want, but only until you provide repaired Ultron)
-- Four Utwig ships (repeat as often as you want, but only until you provide repaired Ultron)
-- Twelve Yehat ships (your fleet can be refilled with rebel Yehat ships as many times as you want, but require at least 1-gamemonth intervals.) However, to accomplish this, you must first start the Yehat civil war, which can only be done if you have a Shofixti ship with you. And you cannot build them... (And without the escape pod, you cannot convince Tanaka.)
-- Four Zoqfot ships (once)
Acquiring Melnorme credits:
-- There are 10 Rainbow worlds in the SC2 universe, and each one is worth 500 credits.
-- The Umgah will also give 500 biounits once they are dezombified. N/A, see above.
-- Life forms (biological scan on uninhabitated planets) can be stunned and captured and sold to the Melnorme. The most life-rich planet is Gamma Geminorum with 341 units, but it is rather far.
Notes on fuel use:
-- The portal spawner will use 10 units of fuel per use.
-- Each planet landing will consume somewhere between 0.1 to 1.0 units of fuel.
-- Escaping a battle with the SIS ship is umpossible until it no longer matters.
-- Hyperspace travel costs fuel approximately 1 unit per 10.0 coordinates. The exact means how this is calculated are somewhat sketchy. Internally, the fuel amount is maintained 100-multiplied so that 5 fuel units is stored as an integer value of 500. The distance calculation uses a 4-bit fraction.