OK, yes, so a transfer, then.
VFIAX is a 500 index fund, so not a total stock market fund (like VTSAX). Putting some of that money into midcap and small indexes is a great idea, because it gives you even broader market exposure.
VTSAX is an effective one-stop shop if you had to pick a single fund to invest in. VFIAX isn't bad at all, either, but you lose out on some of the volatility (greater risk/greater reward) of those midcap stocks.
to that end, the largecap stocks are generally more reliable with far less turnover than the emerging stocks, so you probably want to proportion it something like 70/20/10 from large-mid-small. Those mid and small also typically have higher expense ratios, so that kind of balancing reduces the effect of those larger fees.
I'm no expert, but I think that getting an idea of the actual market representation of prime-large-mid-small cap stocks, one can easily make their own portfolio of total stock exposure by matching that proportion with their own allocation into various representative index funds. In fact, this is what people do, anyway. You may also want to toss in an international index fund at some point. Though I think this isn't entirely accurate, I do like
Jim collin's idea that investing entirely in something like VFIAX or VTSAX uS stocks, you are already investing "internationally" because those major companies (Coke, Apple, Microsoft, etc) have international market share. (not entirely accurate because, well, they are simply different companies. Nestle, for example, is not a US company). Still, the success of Apple and Coke absolutely does depend on the success of the global economy. The only thing you miss by not going into an international equity fund is another collection of companies (generally at a higher exp ratio) to invest in.
EDIT: can you invest in VTSAX/VTSMX? It looks like you have nearly full access to all of Vanguard offerings? I would recommend that over VFIAX, and maybe 2-3% into VTBLX