Des James, from Llanymynech, near Oswestry, said such unpleasant questioning during his evidence to the 30 day inquest into his daughter Cheryl's death had been immensely upsetting.
Receiving a letter from Milly Dowler's grandmother expressing her own disgust at the claims, Mr James said he was touched by her response.
The parents of Cheryl James said it is hard to accept that they took her to the Army camp where her life ended.
Des and Doreen James, who live in Llanymynech, near Oswestry, are urging people touched by the death of their daughter to make a donation to a fund set up in her memory.
Money raised for the Cheryl Marie Snowflake Tribute fund goes to Hope House Hospice, just a few miles from her parents' home.
They say they feel very privileged to have been Cheryl's parents.
Mr and Mrs James said: "Almost every witness at the inquest referred to her as happy, smiling, bubbly, fun, generous and kind.
"We love her dearly, we miss her every day and we always will.
"It is so hard to accept that we delivered her to that awful camp where we truly believed she would be safe from harm – as the parent of a child who joins the armed forces, you are prepared to accept that one day they may be sent to war and you accept the consequences of that.
"What you don't expect is to be told that your 18-year-old daughter has been found dead from a gunshot wound to the head, alone in the trees near the gate she was tasked with guarding."
"We can only hope something good will come of this horrific journey but we cannot be sure of that."
The couple said that they dearly wanted Cheryl's life to have made a difference and the the fund was intended to be a genuine celebration of the happiness she brought them.
"We wanted to enable her friends, her family and anyone touched by her story, to make a donation in support of the magnificent work of Hope House," Mr James said.
"Cheryl's legacy will remain in our support of the Hope House Children's Hospice, near Oswestry, in a memorial fund set up in her name which has already created close to £30,000."
One of her best friends, Kirstie Mansfield, joined Mr James in taking part in a Santa Run for Hope House.
She gave evidence at the inquest and attended the last day.
She said: "She was beautiful and giggly with an infectious personality. She was only ever in a good mood and were were two young women focused on having a good time"
Anyone touched by Cheryl's story can make a donation in her memory at: http://cheryl-marie-james.muchloved.com
On Friday coroner, Judge Brian Barker QC announced his verdict that 18-year-old Cheryl had died as a result of suicide while on lone guard duty at Deepcut Army Barracks.
Mr James said questioning from Surrey Police's legal counsel, John Beggs QC, while he was giving evidence had been extraordinary.
"My wife and I were made to feel as though we were on trial and we felt as though our family was undermined at every opportunity," he said.
"We had written to Surrey Police during their 2002 investigation into Cheryl's death, asking questions and raising some perfectly reasonable concerns. Mr Beggs suggested that our enquiries had been distracting Surrey Police from "more pressing enquiries" such as the search for Milly Dowler's killer or the M25 rapist.
"Milly Dowler's grandmother was so upset at this that she took the time to write to me care of the court to say that she and the family had been 'disgusted' at the suggestion by Surrey Police that we had been squandering police time or that Surrey would 'use Milly as an excuse not to help' us.
"This needlessly unpleasant line of questioning hurt both our family and the Dowler family."
Mr and Mrs James say the inquest had not given them the answers to questions they had been asked in the 20 years since her death.
"Surrey Police abandoned the scene of Cheryl's death within 40 minutes of their arrival and agreed that the Military Police should be permitted to investigate it for themselves," Mr James said.
"As a result, the military were allowed to investigate the matter for themselves and they failed to take even the most basic steps to preserve the scene, retain forensic evidence or conduct any form of independent inquiry into a sudden death.
"Whatever actually happened in that final hour of Cheryl's life, we may never know.
"What we do know is that if she had not been ordered to guard the gate armed and alone, she would still be alive today.
"The standing order that a female guard should not be armed and alone was repeatedly ignored.
"The camp command, by their own admission, were not even aware of the order. Yet to date, no one has been held accountable."
Mr James said that it was "deeply regrettable" that the experiences of other young women and men were ruled out of the scope of the inquest.
"Those that attended because they were able to give evidence about Cheryl but could not speak about their own experiences in detail could be seen at times to visibly shake with the shock of their memories and when the names of certain people were put to them," he claimed.
"The victims of abuse at Deepcut are still suffering. Many to this day have not even told their families about their experiences.
"They have been airbrushed out of history, forgotten because successive governments refused to act.
"However we have established that Deepcut was a toxic, abusive and deeply dysfunctional environment that caused immense damage to these kids.
"The MOD must ensure that those who were its victims are heard and cared for."