This is the same [or modern incarnation of the same] course I did when I started out and is well worth doing
I would be inclined to pay heed to Doobin's comments regarding what a business is actually worth.... As he says, goodwill is worth nothing, signed long term contracts yes, but a list of names of people who have previously spent money with a business has no real value at all.
What about the name? Is it your previous employer's own name? Is it a well known local 'household' name. If so, that may be worth something, but not as much as you might think.... There's no reason why you can't mention it when looking for new business whether you buy it or not. 'Hi, yes, I used to work for so and so before he retired, now I've set up on my own using everything he taught me'....
And tools and equipment are also worth looking at a bit more closely. Bear in mind these are all second hand items so you need to be factoring in the eventual cost of replacememt as well. You also have no warranty on this stuff, so make an allowance for repairs and maintenance.
You may find that when you've produced your final business plan you would actually be no worse off if you went out and selectively bought only the stuff YOU need - rather than everything accumulated by someone else - brand/nearly new and with warranty, on a structured finance deal.
I know you want to see your employer right into his retirement and that is commendable, but don't let that blur your outlook and see you saddled with something which you could have had for free. In many cases it is no easier taking over and making an existing business work than starting from scratch, in some instances it's even more difficult.
Are you taking the business on part way through work? As part of this purchase do you get any work in progress which you can invoice straight away to begin generating income? Will what you buy generate any income at all if you do no marketing, does it give you orders in the bag? Or are you going to have to pound the pavements like every other new entrant anyway? But with the handicap of a larger overhead....
Just make sure you go through EVERYTHING until you can clearly prove the payback. And remember, if your current employer has not made adequate provision for his retirement then that's not your responsibility. It's tough enough starting out these days without making things doubly difficult for yourself...
Good luck with it!