You will never generate a form 8606, because you are never putting after-tax money in a traditional IRA, that's the only time that form is created.
If you do a direct rollover to a Roth IRA, you will get a form 1099-R from the 401(k) plan showing the distribution, and a form 5498 from the receiving account. The 1099-R is reported on your tax return, the 5498 is for your records (it is not needed for the tax return and the broker will often wait until May to issue it). The rollover is taxable.
If you do a direct rollover to a traditional IRA, and then a conversion from a traditional IRA to a Roth IRA, you will get a 1099-R from the 401k and the IRA, and a 5498 from the IRA and the Roth IRA. Again, the 5498s are for your records, and both 1099-Rs are reported in Turbotax. The rollover from 401k to IRA is not taxable (but must be reported) and the conversion from IRA to Roth IRA is reported and taxable.
