A couple of things right off the bat:
1. The different in performance between 100/0, 90/10, and 80/20 stock/bond splits are minimal because of the rebalancing bonus you obtain, so don't feel like being 90/10 would decrease your returns very much.
2. According to Morningstar, RAFGX and RIGGX (especially RAFGX) have a LOT of money in cash (13.12% and 4.95% respectively). This means with your current AA, you have 7.4% in cash, so you're not 100% stocks anyway. Since cash gets you no return, and inflation eats away at its value, you get negative real return on cash.
So, because of the high cash allocations in the American Funds doing nothing for you and the fee difference (costs matter!), I would recommend putting the bulk of your account into the total retirement 2060 fund VTTSX, and the remainder into the Vanguard extended market fund (VEXAX) since you have stated you want to tilt to small/mid-cap.
One possible allocation then would be:
80% VTTSX
20% VEXAX
This has an average ER of 0.16%, for an annual savings of $21.05 per year for every $10,000 you have invested.
Morningstar Instant X-Ray (
http://portfolio.morningstar.com/Rtport/Free/InstantXRayDEntry.aspx ) shows you'd have a pretty similar mid/small cap tilt to your current portfolio. American Funds tends to have a Growth Tilt (whereas Value, historically, has had a higher return and higher risk).
You'd be tilted a bit more towards US than international than you currently are. You're currently about 65%/35% US/international, whereas the allocation I have above is 75%/25%. If that doesn't bother you, I'd stick with the vanguard-only portfolio. If you really would rather have a higher international allocation, I don't think it would be a big deal to replace a bit of VTTSX with RIGGX to restore the balance, giving:
70% VTTSX
20% VEXAX
10% RIGGX
That brings your average ER down to 0.21%, so you're saving $16.75 per year per $10,000 invested over the original portfolio.
Keep in mind that the dollar amounts saved are just on the expense ratio. American Funds' funds have higher turnover, which incurs more costs that you don't see in the ER.