I used to remember when a shuttle used to be in a Starship ... yes ,INSIDE a starship. Why can't we use our Starships to get from A to B and then when / if (hint hint) we have a mission that involves a shuttle, we just launch from the Starship. Would that not be a better than having to go to a base?
You CAN switch to your shuttle at any time. You don't need to go to a star base to do so. This details how. I believe you can also simply switch to your shuttle's bridge and use one of the consoles to switch your active ship to the shuttlecraft.