Been there, done that, here's what I did...
First, make sure wherever you end up, that they do the conversion to an inherited IRA properly, if they don't you can be hit with major penalties and could be forced to take out all the money over a 5 year period. As long as you go with one of the big firms (Vanguard, Fidelity, etc...) you'll be fine because they know exactly what to do. It has to be set up as a beneficiary/inherited IRA.
Second, if you aren't up to speed on basic investing, you can absolutely just leave it "as is" once transferred to an an inherited IRA for a little while. I left mine alone with the professional management my dad had originally set up for it, and with their suggestions based off their questionnaire for me for about 3-4 months until I'd done my research and felt comfortable taking it over. This does mean that I paid for the professional management during that time out of my own pocket (or they can take the fee from the actual account without any penalty to you), but until I felt right about my moves, that seemed like the best solution at the time for me - I had zero investing experience, so I was mostly afraid about screwing something up.
Short term management fees are not as bad as just leaving it that way forever, and at least I wasn't feeling overwhelmed about having to do everything right NOW (dealing with the death and other aspects and trying to learn about investing was bad enough...). But looking back now, I would suggest if the inherited account has professional management, cancel it during the transfer and just let whatever funds that the IRA has sit in your inherited IRA until you feel confident about buying/selling to get your selections. There really isn't any need to pay for professional management at all. I would not sell off everything until you know what you want to buy - going to all cash means you'd lose out on any growth while you decide, and even if the current funds are crummy overall, they'd still likely be earning something during your research/learning phase.
Once you've got a good idea of what you want to do, then sell off anything you don't want and buy whatever you'd like. I had to create a self-managed account to move the funds over to since I did keep that pro management, but it was easy and completed in one day and after that I sold off all the junk and bought what I wanted.
The required minimum distributions are based off of your age and life expectancy. In my case (Fidelity) does the calculation and distribution automatically on the date I specified and automatically takes out taxes at the rate I wanted. Pretty sure Vanguard or any of the other ones would be able to do the same.
I am using the amount to top off my and my husband's Roths (which I do think is the best move), but you can roll it to a taxable or just take the cash if that's what works for you.
http://jlcollinsnh.com/stock-series/^This series was instrumental in helping me figure out everything and get my asset allocation figured out
http://www.bogleheads.org/wiki/Investment_policy_statementGood idea to get this figured out ASAP
For Vanguard, I'd recommend calling their Concierge Services instead of the regular number. Since you've got a decent amount in that IRA, they should be very happy to help you personally to get it shifted over and set up correctly, including getting a Roth IRA set up for you to fund.
https://investor.vanguard.com/what-we-offer/personal-services/concierge-servicesFinally, very sorry for your loss. I've been there with that part too, and it can be very difficult to get this sort of thing done and deal with a death in the family and I do hope you are doing as best you can under the circumstances. But do remember - it's okay to take a month or two to get your head on straight and deal with the money stuff when you're good and ready.