Advice on lump-sum retirement withdrawl?

I'm seeking guidance on the trade-offs involved in withdrawing a lump sum from my retirement accounts for a home purchase. I'm 63 and plan to retire within two years, at which point I will sell my current house and move to a more expensive home in a new town. I prefer not to take out a mortgage in retirement, so I anticipate the need to remove at least $100K from either my 401K (current value $1.25M, containing both pre- and post-tax contributions) or my Roth IRA ($120K). What issues should be considered when deciding to withdraw from the 401K vs. the Roth IRA? (Just in case it's relevant, my other assets include non-retirement savings & investments amounting to $220K and my current paid-for home worth about $200K). Thanks in advance.