VSOP87D: What are the purpose of the initial columns in the VSOP87D data?
First, the data in most of these columns is not required for the computation of planetary positions using the theory if the 'second' form equation is used. The terms are, using the order of the example of Jupiter VSOP 87D's third line ...

4510 ...

"4" means the 'version code', i.e., this is the "D" version of the theory which allows computation of the heliocentric rectangular coordinates of the planet for the ecliptic of date. A "3" would be for the spherical heliocentric coordinates for the ecliptic of date.

"5" is the 'body' code, Jupiter being the FIFTH planet. Mercury would be planet '1', for example.

"1" is the 'index of coordinate', meaning in this example that this line is part of the 'longitude' coordinate calculation. Later lines show a '2' for the B (or latitude) coordinate or '3' for the R (radial or distance) coordinate)

"0" is the 'degree' or power of the time variable. Here, terms are multiplied by T to the ZERO power (or 1). Later terms are multiplied by successively higher powers of T.

3 
... is simply the sequential number of this line in this series. Jupiter has 5 series (each multiplied by a higher power of T), so this number 'resets' for each series.

The next 12 terms, mostly zeros in this example, are the 'coefficients of mean longitude'. As near as I can tell, these coefficients are used to correct mean longitude quantities for secular perturbations. They are used only in the first form of the equation as shown below with the next two terms:

The next two terms are amplitudes S and K, used in the first form of the positional equation:

T**alpha * (S sin phi + K cos phi)

where phi = sum[i, 1 thru 12] [a(i) * lambda(i)] and lambda(i) values are given for each solar system body in the explanatory text.

The final 3 terms are Amplitude A, Amplitude B and Phase C for use in the second form of the equations to calculate position:

T**alpha * A * cos(B + CT)

... with T being time in Julian centuries, and alpha the 'power' of T.

My comment in the original question about the terms being 'off' by several orders of magnitude is moot ... for convenience either in calculating or printing, Meeus multiplied the terms by 10**8, then corrects for it later. This probably facilitated better computation on machines of the time it was written and also made for neater printing in the book.

The document provided by barrycarter, along with some other study of planetary motion allowed me to finally understand this, thanks!