Great question and no you are in the right place!

First off, let me point you towards some great books to really give you an insight into white experiences during the Bush War. David Caute's Under the Skin is an excellent (but hard to find) account of the experience for most white Rhodesians during the war. Peter Godwin and Ian Hancock's Rhodesian's Never Die also provides a really good insight into the struggle farmers faced during the 1960s and 1970s. Finally, Terence Ranger and Ngwabi Bhebe's Society in Zimbabwe's Liberation War provides a very good companion work to the two named above. I'd also suggest just having a gander at any of the many, many, many autobiographies and memoirs which have been written by white Rhodesians who lived through the period, including many farmers or whose families owned farms. By far the best one for a look at the experience of white farmers is Lauren St. John's, Rainbow's End: A Memoir of Childhood, War, and an African Farm (2007 I think). But with that out of the way, lets answer your questions.

What did the Rhodesian farmers experience during the Bush War?

Simple answer is that it depended both on the time and the place. Broadly speaking, white societies who lived in towards the north-east and east of the country (where it bordered Mozambique) suffered the brunt of the guerrilla attacks. Raids on white farms, although deemed barbaric and a sign of why Rhodesia had to fight back, were not common occurrences - hence the fierce shocked reaction they received from the white population when they did occur. The most well-known assault on a white farm - the Altena Farm attack - didn't happen until 1972 but it arguably marked the beginning of the second phase of the war, and a different type of war than before.

Let's use Altena Farm as an example of what a raid on a white farm looked like. On 21 Dec 1972, one of the nationalist groups ZANLA attacked the Altena Farm located in the Centenary district of Mashonaland Central (located right at the top of Zimbabwe, and with a large and mountainous border to Mozambique). A group of 21 ZANLA fighters, led by Rex Nhongo, crossed the border form Mozambique where they had been trained and armed by the Mozambique FRELIMO nationalist independence movement. Armed with AK47s, RPG-7s, molotov cocktails and landmines, the group surrounded the isolated farmhouse very early in the morning, before the sun was up, and opened fire. The attack lasted just thirty seconds and the guerillas were gone before anyone could call for help. The farmhouse was occupied by a woman and four children at the time. An 8 year old girl Jane was the only one wounded and only in the foot (probably by a metal splinter from an RPG blast). The family escaped to a nearby farm called Whistlefield Farm. They called in the army who arrived the following morning (as the drive from the nearest army base was over four hours).

Before the attack took place, the ZANLA troops laid landmines on the road to the farm. When the army arrived, their jeep detonated a landmine, wounding three and killing one. That night (23 Dec) Whistlefield Farm (where the four children and their mother had taken shelter with the farmer and his daughter) was attacked with RPGs, AKs, and grenades. The man and his daughter were both wounded in the attack, and a second landmine was placed on the road to the farm but was detected by the army. What this attack showed was a deliberate policy of the attacking white farmers with an intent to kill. Farmers were attacked because their properties were often far from help, and would permit the guerrillas enough time to escape the area before the army arrived, or at least give them enough of a head-start.

Obviously, this is just one example of an attack on a farm, but it provides a good indication of how horrible and how difficult it was for white farmers to protect themselves or their families. Many farms got through the war unscathed but the installation of grenade screens on the windows, the purchasing of ex-military weapons (usually under the table from the local army) and the reluctance of many whites to vacate their farms, even in dangerous areas, provide an indication of the tenacity and resilience white farmers put up in the face of the fear of guerrilla attacks.

There were other implications from the Bush War as well, in terms of the wider economic sanctions that essentially closed the market for farm produce in Rhodesia, and the difficulties of getting the parts needed to run the mechanical aspects of modern agricultural farms but despite being more widespread, these were not as recognised as the dangers of attacks from the 'Ters'.

Where can I read accounts about the Vietnam Veterans who were hired to protect the farms?

What you are talking about, I presume, are the 'Range Detectives'. These were foreign mercenaries, mostly American and often Vietnam veterans, who were hired by the BSAP in order to combat cattle rustling on the Tribal Trust Lands. Here's a picture of one. And here's some pictures from a scan of an article about them. Page 1 , Page 2 , Page 3 , Page 4 , Page 5. I don't know about anyone who hired US vets to protect their farms personally, but there may be something in one of my books so I'll have a look!

Most literature doesn't deal with them directly, but also have a read of Ward Churchill 's article about the US mercenaries who fought in the Rhodesian War, and Gerald Horne's From the Barrel of a Gun. There's a great little blog-style thing here about it all as well

Hope all this helps! Any questions, just ask away.