Well, what do you want to calculate? Timing? DV? Both?
Generally speaking, the idea of a deorbit burn is NOT to land you on a base, but to bring you to the entry interface, a virtual waypoint at the top of the atmosphere, where orbital mechanics cease to decide where you are going and aerodynamic forces take over again. Often, this point is about 100-120 km above the surface for Earth.
This point needs to be passed with a specific glide angle - which angle you need depends on the spacecraft, the Shuttle prefers about -0.7°-1.5°, Apollo used 6°.
And this point needs to be far enough away from the base, that you can comfortably glide towards it (in a gliding or a skip reentry, both allow you to aim for a specific landing site) or just close enough that a steep unguided ballistic reentry brings you close to the landing site (but hitting it perfectly is impossible then). And close enough, that you can reach it at all.
So, for knowing what you need for planning the deorbit burn, you need to know the characteristics of the spacecraft - how far do you travel when you step on the brakes during reentry and slow down as fast as heatshield and structure can take? How far can you travel by keeping deceleration low and glide as long as you can without loosing control? How far away from the original groundtrack can you get?
The BaseSync and Glideslope MFD's can work in combi mode to do a de-orbit burn with base alignment. Here's a video showing how to de-orbit the XR5 from the default 'In Orbit' scenario for landing on Cape Canaveral: