Having established that Robin Hood is real within the Doctor Who universe you may wish to explore his further adventures. You could have a whole campaign, with the players taking the role of the famous outlaw and his merry men.
The tales of Robin Hood can easily be emulated with the rules. Each outlaw is usually identifiable by a distinctive trait, indicating that they specialise in one particular trait. This allows characters to shine while working together in a group.
Awareness is excellent for tracking targets through the woods or identifying potential traps. Coordination is a must to be an accurate archer. Ingenuity is useful for pulling off successful heists and ruses. Presence is good for bards and to have enough charisma to be a folk hero. Resolve can allow characters to resist torture or keep going when things aren’t going well. Strength is good for close combat and to represent characters like Little John (at least the version of legend).
Bold characters like Robin Hood might have a combination of Attractive, Brave, Charming and Lucky. Those wanting to escape from guards by blending in might choose Face In The Crowd and Run For Your Life! to just outrun pursuers. Most outlaws should select the Outcast trait to represent that they are hunted by the local authorities (although the peasants they help will still aide them).
Athletics, fighting, marksmanship and survival should be a priority for most outlaws, with subterfuge being useful for thefts and convince good for those who are prefer to use tricks. Technology and transport shouldn’t be selected without good reason.
Players can create new Merry Men if they wish. These could include stranded time travellers and aliens, if you wish to have more of a connection to the Doctor Who universe. Non-human aliens might be able to disguise their appearance so as not to alarm the locals.
At the end of ‘Robot of Sherwood’ the Castle of Nottingham has been partially damaged by the spaceship taking off and the Sheriff apparently killed after he plunged into a vat of gold (but given his non-human body he might still survive).
It wouldn’t take long for a new Sheriff to be appointed, with the people still oppressed and Robin Hood and his Merry Men hunted. The typical plots in such a setup would include:
STEAL FROM THE RICH, GIVE TO THE POOR
The outlaws learn about some treasure or other valuable item within the local area. Can they steal it and get away clean? The exact nature of the treasure, its location and the security surrounding it will make the adventure varied. There will always be the possibility that it is a trap.
HELP THE OPPRESSED
The peasants live miserable lives and the local authority only make it worse. They might once again be forced into slavery or their homes and property taken from them. The outlaws must fight to free them, thus winning their support.
Whether it be Maid Marian, an outlaw or a local there is usually someone in the dungeons that needs rescuing. This plot can naturally occur if anyone is captured during an adventure. It can also be the start of an adventure if the prisoner has valuable information or abilities the outlaws need to advance their own agenda.
Some of the lore about Robin Hood indicate that his Merry Men consisted of over a hundred men. This gives you plenty of room to introduce new members of the group, either as PCs or NPCs.
NPCs might have unique skills and abilities that can help the outlaws. The group will have to decide if their personality and motives make them suitable candidates. Their agenda can create adventure ideas, such as someone who seeks revenge or wants to keep what they steal rather than give to the poor. When these conflict with the PCs goals this can create friction.
Some new recruits might not be what they seem. They could be working for the Sheriff to gain valuable information or lure them into a trap. They could also be shape shifting aliens in disguise.
This type of story line concentrates of the particular time period. Whether this be the state of their society, their political relationship with countries, the absence of Richard the Lionheart or how people are treated based on their station in life, gender or skin colour.
This can be combined with the other plots to give historical context.
LEGENDS AND THE FUTURE
We don’t know everything that Clara told the outlaws (nor what Robin might have glimpsed on the spaceships database). An adventure could be based around events which the group have foreknowledge of.
The layer of legend means that they can’t be sure exactly what does happen. Can they engineer evens the way they were supposed to happen or will they discover that the stories told were wrong?
Now that Robin Hood and his Merry Men are aware of threats from outer space they might be more watchful for them. They can bring their guerrilla tactics to repel alien invaders or prevent further alliances with the Sheriff.
The robots could have left further advanced technology in the local area (maybe scattered after their ship exploded) that could attract others. This technology could fall into the wrong hands and cause further trouble until the outlaws can acquire it.
If you want to take the outlaws further afield they might here of others who fight aliens and exchange information. This could lead to an organisation that protects the UK from other worldly forces during the 12th century.
For the most part, no matter which plot you choose, the status quo should remain. The New Sheriff is still in power (if a little worse off), the Outlaws retreat back to the safety of the forest and the struggle continues.
Not to say that individual characters can’t grow. Their relationships can grow, they can re-evaluate their methods and their reputation with the locals might improve or worsen depending on how successful they are.
No matter what adventures should strive to be filled with daring do and witty banter. PCs are playing the role of heroes to cover their own fears and weaknesses to inspire others. They oppose wickedness and hope that they live up to their legends.