This should be fairly straight forward.
Accommodation is plentiful. There is a camp site, two pubs (The Crown & Golden Lion) and several B&Bs in Horton in Ribblesdale. Public transport links are reasonable and include the Settle / Carlisle line.
The ascent of Pen-y-Ghent from Horton in Ribblesdale by the Pennine Way is clear and easy. It should not take too long. Alternatively, if you approach from the south there is a very short scamble near the top.
You can use the railway to reach Ribblehead to tackle Whernside and Ingleborough. Walk back to Horton in Ribblesdale by the traditional Three Peaks route. The Station at Ribblehead and Hill Inn at Chapel-le-Dale will provide welcome refreshment. Navigation is easy, thanks to (mostly) clear and well maintained paths. The direct ascent of Whernside from Winterscales Farm should be avoided for environmental issues, and its steep!
Overall, a not too demanding expedition, I'm certain that you will enjoy it. Good luck.