3d drawing based on movable planes?

to take a break from my other game project, a puzzle game similar to Cyan's OBDUCTION, i decided to take a look at some apps on my phone and found some inspiration for a completely different idea: a 3d drawing tool. my idea is that there are 2 planes, a vertical and horizontal, that can be moved along their respective axis by small spherical handles on the corners, which can be dragged by the mouse. And I want to be able to freely rotate the camera around these planes, but also have a button on the UI that moves it to the default, top, and front views. and finally, the tricky part, i want to be able to select one of the 2 planes with a different handle and draw lines on them with my mouse, which would then stay in their position even after the planes are moved. this is the very basic functionality, but i have no idea how to even start with the code.

so far i have the default free look cam script on my main camera and it rotates the view when i move my mouse, but that isnt exactly what im looking for.

does anyone have a good idea as to where i can start with this?