Exactly. It is a huge simplification but it may help to compute the resulting (parallel/serial) resistance and capacitor.So what you were really asking is whether the second circuit is valid as an approximate equivalent of the first. Even that question is a little vague. Equivalent in terms of input impedance or equivalent in terms of some two-port parameter like vout/vin or whatever (though no vout or vin are labelled on the diagram).
That is good idea and I'll simulate these circuits.Why dont you calculate both, compare results and post us in :)
I'll take a look at these hits.Look up "RC transmission line" on the web. I got several thousand hits. It is a special form of lossy delay line that has dispersion.