What CJ said...that's the place to begin. If you're happy with the frameset tins, that part of the project is done. Tires, seals and brake shoes don't improve with age, they just deteriorate and become dangerous. Blasting and repainting the wheels & hubs while everything is apart makes a lot of sense. And, this model has painted brake plates so those can be refinished at the same time...easily. The lower fork legs are also painted silver on the `79, easily refinished. The earlier models had polished brake plates and brushed-polished lower fork legs, much more labor-intensive to restore (although that can be done with this model, if desired). Check the fork action and the condition of the fork boots. Taking the fork legs apart is easy and it necessary to replace the oil seals...which don't owe you anything after 41 years. From there, it's easy to clean out the fork internals (also a great time to refinish the lowers; then install the new seals, refill the fork legs with clean 15W fork oil and you've rebuilt the front end. If the fork boots (gators) are crunchy, replace them. The TL bracket, exhaust guards and brake pedal were all painted low-gloss black which makes them very easy to refinish, for next to no money at all.
All of the above can be done in a couple of afternoons using less than $30 worth of rattlecan paint. The difference, visually, will be like night & day. The front end will need about $60 in parts & oil. New brake shoes, dust seals, wheel bearings should cost another $60, depending which ones you choose.
Of all the models, as long as the HL ears are intact, the `79 is the most DIY-friendly (and budget friendly) in terms of refinishing. There is nothing special about the original single-stage yellow enamel and yellow tends to hide small surface imperfections. If you do ultimately decide that you'd be happier with fresh paint, 3 rattlecans of single-stage enamel should be plenty to do the frameset & fenders, if you want to keep the budget to the minimum. Just FYI, at the extreme high end...epoxy primer, 2-stage (basecoat/clearcoat) urethane paint would require somewhere around $250-300 worth of paint materials.