Mark,
IF I remember correctly the Pamp had isolated their ships hydraulic system and installed a small accumulator and hydraulic pump and then rebuilt the valves and packing for the periscopes so they could be raised and lowered. What that means for you is that you can buy a small commerical 110VAC pump and get a small accumulator and operate your systems cheaply.
Doing it cheaply
that is to ass/u/me that you have no residual 40+ year old contaminated fluid in the lines and you have all of the packings onboard for all of the connections/valves in your periscope system AND you can find someone to donate the pump&accumulator&fluid and the hoses to hook them up.
Now with the Torsk, I did work on part of the hydraulics in the ATR for the rudder controls and stern planes and found that a LOT of the packings were missing and there were blanking plates installed and incredibly some of the joints were only hand tight at the pumps.. The purpose for working on the hydraulics in the ATR a few years ago was to get them to stop leaking
and not to make them operational once more. Sadly we did have a 110VAC pump&accumulator donated to the Torsk and later delivered to a local volunteers house only to have it set outside in his yard for years while it was being decided if it was going to be used or not and the accumulator tank was to large to fit through the hatches and honestly I don't know what happened to that system and I seriously doubt that the volunteer has it anymore at his house.
To answer your question correctly Mark, remember that no matter what you have to have a supply and return line attached to an accumulator which serves 2 purposes and you also have to have a hydraulic pump.. Personally I would look into getting a small portable self contained hydraulic unit and then slowly drain out the old lines, replace all of the packings and seals and then slowly start pressurizing your hydraulic systems one at a time. Another thing to remember is whatever you are trying to operate has grease fittings that may or maynot have been used in years and in the case of the periscopes you may have blocks holding them in place so they don't lower with or without pressure.
Another thing to remember is once you start pressurizing your hydraulic systems they will need to be bled carefully while someone is watching the level in the accumulator (think about bleeding the brakes in a car) and then you will need to start putting drip pans under all of the valves in that system because they will start leaking again and that leads to other issues with having tourista's onboard and not a full time crew to constantly clean up the drips before they become to big.