Many come without a hood. They are a real PITA to put on an off and the method of securing them is difficult at best with the loader on. If you really need one Vons Mogs sells Fiberglass ones
http://www.vonsmog.com/newunimoghoods.html. There is someone on the Unimog Exchange
http://www.unimog.net/exchange/ parting one out, but I expect unless you can go pick it up the cost to ship would be outrageous. The biggest issue with no hood is the fuse boxes are exposed to the weather. There is supposed to be clear plastic covers over the fuses to keep them dry but these seem to disappear. It just means you need to keep an eye on the fuse clips and clean the inevitable corrosion off them on occasion.
Yes drain the fuel tank and take a flashlight and look inside the tank for growth and contamination. Some folks have had a heck of time fighting this as if its in there its going to come out and plug up the fuel system. Some of that crap is biological so even if you clean out the tank the fuel system will reintroduce it. The primer pumps on most SEEs are crap. if you need to unscrew a serrated plastic cap, that's the old style and it questionable that it will work. Its not worth rebuilding. Get the new style Bosch plunger pump. Expedition Imports has them along with the biggest inventory of NOS spares for SEEs.
Yes your hoses are most likely "cooked", its a choice of pay me now or pay me later. There is still some life left in the hoses as is but I would suggest getting some oil absorbent pads to throw in the tool boxes for when a hose fails. I wouldn't set it as priority until you figure out if everything is working. Don't buy NOS hoses, just go over to hydraulic hose store and have them make up a set.
If you go through this thread you will discover you are missing a key system to go through. Its a PITA but my strong suggestion is go through the air system as its critical to the operation of the SEE and there are a lot of expensive difficult to get to parts that can get damaged by the inevitable crap in the air lines. Start at where the air line that comes from the engine screws into the alcohol injector ( Just ahead of the right rear wheel), to the air pressure regulator and then follow it through to the air tanks. Take a magnet to the line that runs from the inside of the left frame rail just off the air pressure regulator that runs to the air tanks, it its steel, plan on replacing it as its low spot in the system and rots from the inside out and will contribute rust flakes to the air system. You can only go so far easily until you need to lift the cab (difficult) but my guess is the crap introduced from the cross body air line tends to drop out and get caught in the air tanks and some of the check valves before it heads up to the inaccessible locations. By the way, the alcohol injector selector is hopefully set at summer meaning its turned off, don't turn it on until you have verified that the alcohol bottle isn't smashed in and full of dirt. If you plan to use the SEE in freezing conditions then you will need to deal with it or do the smart thing and switch it over to an air dryer.
I would also suggest opening the drains on the differential locks and lubricating them. I did a post on separate thread on how to do this. Its not mentioned anywhere in the military service manuals and it sounds like on many SEEs it hasn't been done and the drain plugs are painted over (they were on mine).
Check the hydraulic cooling fans out back. Take a thin object and see if the fans will turn free. Then look carefully at where the wires go into the fan motor. The grommets rot due to UV and water can leak into the motors ruining them. The military fix is goop them up with RTV and hope. I think there is way of rotating them so the wire is facing down but both of mine were cooked so I replaced them with truck cooling fans off of Ebay. These fans only run when the hydraulics are hot, if they are full of water, they will short an important fuse that controls a lot of the equipment on the back of the SEE like the remote throttle, the remote loader lift, the hydraulic accessories and the rear spotlight.
Last thing go through the lubrication instructions and find every grease fitting and give them a squirt (make sure you read the warnings on overlubing some of them. They are all there but some are a PITA to find. There is one on the transmission that has to be accessed from up top behind the cab after you have deployed the backhoe. Also drain the portal hubs and refill with synthetic gear lube making sure you get the level right. Most equipment don't have portals so people ignore them. Don't do it, the repairs are major PITA if you let them run low and since they don't hold much lube the lube you do put in them needs to be the best you can get in there.
BTW, Nothing I have said is new, its all buried in this thread. I know its painful, but start at post #1 of this thread and go through every post, you will learn a lot about the things that can be a problem with a SEE. Its also worth going in the Misc tech manual forum and look for the thread with the student manuals and the thread that I set up that has a indexed set of the military tech advisories.
Good luck