Absolutely allow the property to transfer to the heirs as part of her estate. You will all get the stepped up basis value of the property, you will not have to pay any capital gains taxes on it if you do sell (assuming the rest of her estate is not large, exceeding $2 million or on that order). Or, if you sell down the road, you will only have to pay the difference between its value when you sell and what it was worth at the time of her death.
The preferable way to do all this is for her to establish right now a Revocable Trust, also known as a Living Trust, and transfer ownership of the property to the trust. She should also create what's known as a "Pour Over Will" to handle assets not directly transferred into the trust. It would also be an exceedingly good idea for her to create an Advanced Healthcare Directive (or any other name it's known under) that dictates what measures, if any, she wants taken to keep her alive as her health falters one day. Same thing with a General/Durable Power of Attorney, etc., etc.
All of these documents together form what's known as her "estate plan." You can create these yourself, but typically people need to hire an attorney to create it. It will probably cost about $1,500 - 2,000 for an attorney to do this for her, but it's invaluable. And by paying now, you will be avoiding future costs upon her death which would likely be much higher (such as probate court fees, property title transfer fees, etc. -- I don't know what they are in NH).
In her trust assignment, she can name her intended heirs as the beneficiaries of the property upon her death. Nothing will have to go through probate since the property is already owned by the trust, and you will not have to re-title the property (unless you all want to for some reason). So while it will cost a few hundred dollars to transfer the title to the trust now, it's pay now or pay later -- you'd have to pay that down the road anyhow upon her death.
Something to keep in mind is that handing down property to multiple heirs can be very thorny and should be avoided at all costs. It is common for them to have differing views of how the property should be disposed or managed. Or they might all agree at first, but then life circumstances change over the years and now they disagree. One might be in need of money and insist on selling, while others want to keep it. What happens if one of the heirs has a child with a medical emergency or loses their job and legitimately wants/needs to sell, but another refuses to sell? Or the house needs repairs or improvements but not everyone is willing to contribute? Or someone is getting divorced and their greedy, soon-to-be-ex-spouse wants "their" share? These a couple of examples, there are many other problems that can arise.
I would highly encourage her to name just one of you as the sole Trustee and executor of her estate, who has the sole decision-making authority on what to do with the property. Or she can direct that it should be sold upon her death and the proceeds divided between you all. Or that the property will be used by everyone equally throughout each year until it is sold, with one person making the decision on when/how to sell, and then the proceeds are divided according to her wishes. Or other variations you can think of. But the primary point is having three co-owners is a dicey proposition to be avoided at all costs.
If part of the equity is needed to pay for her ongoing living expenses as she ages, then a home equity line of credit or reverse mortgage against the property can provide that without having to sell it.
Personally I would not hire a financial planner. There is a ton of free information available that will tell you everything you need to know. But a reputable estate planning lawyer would be a very good idea to get her estate plan created.
