Science Mode

[Miro Beero]

I just tried a science mode.

There should be a hybrid science mode + career mode.

A couple comments:

-Kerbals should still have the option to grow their career and start with 1 star.

-You should still have contracts available. -Gives you something to try to achieve (you just have infinite money to do it)

[Lorunification]

You can just "make" that mode by cheating infinite funds in the beginning of a normal career mode game. That is exactly what you describe.

[Galileo Kerbonaut]

Or set the funds rewarding to a 1000%, fund penalties to its lowest and start with 500000.

Presto

[Superfluous J]

I've not tested this, but somewhere on Reddit HarvesteR said you can (after backing up your save of course) edit your persistent.sfs file and remove the entire SCENARIO block that deals with funds. This will trick the game into letting you do everything for free while keeping the rest of the stuff.