It could have exciting encounters between the characters of both universes. Maybe a time-travel adventure that combines their unique technologies and skills.
Since I haven't read the 'Doctor's Orders' Star Trek novel, it's difficult to say for certain. However, in many Star Trek stories, if it's related to doctor's orders, it could be a character who is in a position of authority on the ship, like the captain. The captain might be involved in decisions related to the doctor's orders, especially if they affect the overall mission. Or perhaps it's a new character introduced specifically for this story, someone who is at the center of a medical mystery that the doctor has to solve through their orders.
Often, you'll find crossovers where characters from both universes meet and interact. Time travel and exploration of strange new worlds are common themes too.
In such a crossover, we could see familiar Doctor Who villains interacting with the Star Trek crew. Maybe the Doctor has to use the TARDIS to help the Enterprise escape a dangerous anomaly. It'd be a mash-up of epic proportions!
Often, fanfiction explores the characters' meeting in alternate realities or during major events. Also, there's a lot of focus on how their technologies and abilities combine to solve problems.
Well, there could be stories where the technology of Star Trek is used to solve problems in the Doctor Who universe, or vice versa. Or perhaps a time travel incident brings characters from both shows together in unexpected ways.
There could be exciting possibilities like combining the advanced tech of Star Trek with Doctor Who's time-travel adventures. But the challenge could be keeping the tones and characters of both shows consistent.
Often in such crossovers, you'll see unique mash-ups of technology and gadgets from both shows. Storylines might involve saving a planet that's at the crossroads of Star Trek and Doctor Who's timelines. Also, there could be fun character interactions as they face challenges that require the combined skills and knowledge of both crews.
It could range from time-travel adventures to intergalactic diplomatic encounters. Maybe a Doctor Who character accidentally lands on a Star Trek starship and chaos ensues!