Going through this now...
Hi Michael,  I recently purchased a '78 Hunter 25 as well- and I've been doing a lot of work on it in the last couple of weeks.  Regarding the bottom paint, it depends on where you live and what your normal cruising waters are like- Some places have high marine growth, and others have hardly any.  Your use of the boat (cruising, racing, both...) also has a bearing on paint selection.  Ask your local marine hardware people about your area and usage, and they will likely recommend a paint for you, and the different paints have different prices.  The H25 should take about one and a half gallons of bottom paint.  New sheets and halyards will run about $0.60 per foot, my guess for price about $135, plus cost of hardware and rigging (unless you splice your old shackles in yourself).  Check out West Marine's home page (http://www.westmarine.com) and see if there's a 'West Advisor' on running rigging.  If not, I'm sure it's in their catalog.  Yard fees for painting vary by location; Here in Key West, I get charged $4.25/foot to haul, $1.75/foot to have it pressure washed, and $35/hour for labor (to have them sand and paint my 25 is approximately 7 hours of labor).  The boatyards here also require that you purchase your paint and supplies from the yard (rather than a discount marine store) to avoid a "retail fee".  You asked about having the whole hull painted.  It can be done (a paint like Awl-Grip is good for this), but it is a bit expensive- My yard estimated $1200 in addition to the bottom paint job I'm having done now.  I elected to wait 'til next year... ;o)  While the boat is on the hard deck, I recommend you get a marine surveyor to look it over- This will cost you about $150 - $200 (In Key West, $9.00/Foot for an insurance valuation survey, $225).  If you get a complete survey, the surveyor will identify problems with the wiring, plumbing, rigging, hull structure, motor, safety equipment, deck fittings, electronics, and many other areas.  This will also give you an idea of what work you will need to accomplish before your boat is seaworthy, much less comfortable.  I was not comfortable with the wiring in my boat, so I spent most of last week relocating my battery and completely re-wiring my boat (as well as adding a new bilge pump and float switch).  I have about 5 more wires to run before that project is complete (and I will post highlights in the photo forum).  Check out all of the plumbing, through-hull fittings, seacocks, and hoses.  The clamps on these hoses are what keeps your boat from sinking!  Any hose that connects to a through hull, and any connection that is below the waterline should be DOUBLE-CLAMPED.   Good luck with your 'new' Hunter 25!  This is a great boat with a TON of character, and a great layout.  Also, there's a WEALTH of good information about Hunter boats in general on this site- Spend some time combing the archives, and you'll come up with more info than you'll ever need on most projects you plan to undertake.  Let us know how it works out!--Jon BastienH23 '2 Sheets to the Wind'H25 'Adagio'