How to take the rail journey Manchester to the North Lakes area of The Lake District

Final Destination Edinburgh or Glasgow

Most of these trains also call at Oxenholme - Lake District

These trains commence their journeys in the station at Manchester Airport and after departure from Piccadilly station they also call at Manchester Oxford Road station

If you can book ahead of travel, so will have reserved seats, and Oxford Road has convenient access from the starting point of your journey, boarding the train there can be a a good option.
At Manchester Piccadilly the access to these trains is more convoluted, as they depart from the platform/track which is furthest from the entrance to the station.

Book Early and Save: Yes

Online Bookings Usually Open: from up to 24 weeks ahead of the travel date (usually); TransPennnine Express (TPE) places its ticket on sale sooner than other UK train operating companies.

Saving money:

If you want to travel at the cheapest possible price, look for the 'Advance tickets', though the four key things worth knowing about booking and using 'Advance' tickets for travel by TPE services are:
(1) The ticket(s) will be valid for the specific departure you select when making a booking.
(2) The ticket(s) cannot either be refunded, if you subsequently change your plans or miss the train due to any circumstances not attributable to the train operator.
(3) They can be exchanged to another departure on this route prior to the departure you have booked - but the price difference with the new ticket will need to be paid (the price will likely have risen since your original booking will need to be paid.
(4) TPE doesn't take Advance tickets off sale until 15 mins prior to departure.

Reservations:

All types of ticket booked at least 15 minutes ahead of travel for TPE trains have complimentary seat reservation.

If you book and Advance ticket(s) you have to travel on the train shown on the reservation, which will be the specific departure you selected when making a booking.
Though on boarding, you won't have to occupy the seat(s) you have been assigned for your ticket to be valid.

If you book Anytime or Off-Peak tickets you will be provided with a reservation(s) on the departure you selected when making a booking, but are able to transfer the reservation to any other valid departure on your travel date.
You can do this by contacting the TPE social media team, or at a station ticket desk.

What is unusual about travelling with TPE is that these reservations can be arranged up to around 15 minutes prior to departure - which is a much shorter time limit than the norm.

Travelling on Saturday-Sunday

Tickets are usually available 12 weeks ahead of the travel date, but maintenance work on the route is periodically undertaken at weekends and if it is scheduled on your travel date, it can affect when tickets will be released for sale.

If you're looking up a journey less than 12 weeks ahead and Advance tickets aren't available, it can be a good indication that works will be impacting on your travel date.
It can be worth checking this on the National Rail website - enter TransPennine Express as the operator.

Booking at the station

As TPE doesn't take Advance tickets off sale until 15 mins prior to departure, if you will be booking walk-up tickets at the station try to avoid booking at the last minute.

Offers and deals:

TPE offers a group deal for when groups of 3 - 9 adults are travelling together and Advance tickets are booked online - make sure you see the 'G' symbol which indicates that the discount has been applied.
You can save 33% of the total costs of the tickets and no Railcard is required.