Why bother with complicated rocket logistics at all?
This mod adds a logistic teleporter. It is not fit for human use, but it can exchange items with another teleporter on a different planet. When not functional, the teleporter acts as a container you can fill up with whatever you want. After it is activated, it begins the teleportation cycle, which takes 20 seconds and uses 150 MW of power, for a total of 3 GJ. After a successful teleportation, the inventories of the source and destination teleporters will be exchanged. Since you need to have built a teleporter on both planets, you'll still have to fly a space platform there initially, but after that, you can handle all of your logistics with teleportation, as long as you have enough electricity.
You can activate the teleporter from its gui, or set it automatically activate when it is full. More complicated conditions can use the circuit network. Send a teleporter a planet signal (from the space tab) and the teleporter will attempt to start a teleportation cycle with a teleporter on the signaled planet. Modded planets are supported, unless they're doing something really strange. If you have multiple teleporters on a planet and want to be more specific about destinations, you can set a "Link ID," which will attempt to go to the corresponding teleporter. Using anything, everything, or each as a Link ID will link with any teleporter.
Teleporters do not support modules or beacons, and adding them via other mods will likely result in teleporters that don't work. Teleporters must also be the same quality to teleport between them. You can disable this, but you shouldn't unless you know what you're doing.
If you like teleporters but you also haven't completely given up on rocket logistics, you might find Circuit Launchable Rockets or Rocket Cargo Insertion useful, too.