I did this job on a 1985 Cargo about 5 years ago.
The windscreen does need to be removed alright. First thing you need is the correct new panel. You need a spot-weld removal tool - i.e. a small rotary cutter which you mount in a drill chuck for cutting around spot welds. There are a good few spot welds to be cut on the joint between the scuttle panel and the dashboard.You have to grind off the weld nuggets which are left when you remove the old panel. You also need a MIG welder to weld the ends of the scuttle to the "A" pillar of the cab. Most importantly you need a spot welder and an assortment of different electrodes. If you're doing this "in the field" - away from a propoer workshop you will need a generator with at least 4kVA.
The windscreen wipers, linkages and motor all need to be removed.
It's a job best done in the workshop and it really is a 2 man job to remove and replace the windscreen without damaging it.
JD, April 2008